帮你google了一下： Failing to register for Selective Service can be grounds for USCIS to deny Form N-400, Application for Naturalization. Many immigration attorneys will recommend that their clients wait until age 31 to apply to ensure five years of good moral character. 31岁再申请，做个守法好人。
Proving Good Moral Character If It's Too Late to Register If you've passed age 26, it's too late for you to register for the Selective Service. Your chances of qualifying for U.S. citizenship depend on how many years have passed since you were supposed to register and how many years of good moral character you need to show. If you need to show five years of good moral character, then the easiest thing might be to wait until you are age 31 to apply for citizenship.
Proving That You Didn't Know You Were Supposed to Register If you are eager to apply for citizenship before you turn 29 or 31 (as applicable), you may be able to show USCIS that you had no idea that registering was expected of you, and that you therefore didn't "willfully" fail to register, by submitting these along with your naturalization application:
a Status Information Letter from the Selective Service System your sworn declaration, and sworn declarations from people who knew you.
Obtaining a Status Information Letter A Status Information Letter from the Selective Service simply states that you are over-age and therefore no longer required to register. However, you need to get one, because USCIS will refuse to look at the rest of your materials without it.
You can request the Status Information Letter from the Selective Service System website or by calling 847-688-6888.
Drafting a Sworn Declaration Explaining Your Failure to Register Your sworn statement should offer reasons why you failed to learn about the Selective Service registration requirement.
If you attended high school in the U.S., you were probably told about this requirement, and will need to additionally explain why the information did not cause you to register. (For example, perhaps you heard about the requirement but believed it applied only to U.S. citizens.)
You will also have trouble claiming ignorance of the registration requirement if you got your green card either through the amnesty program in the 1980s or more recently, during or after the year 2001. In both cases, people were alerted to their registration obligations.
If possible, get letters from other people who knew you, particularly people in positions of authority, such as a high school teacher. The letters should support your explanation of what happened to result in your not knowing you were supposed to register.
很有可能你已经被登记selective service了。如果你是在美国境内通过Adjustment of Status拿绿卡的，I-485表有一部分是如果你是男士在18岁和26岁之间，你允许uscis帮你自动登记。如果你是在美国境外通过Consular Processing拿移民签证的，我相信移民签证申请表也有一部分是你允许他们帮你自动登记的。你打电话去selective service system问一问。有可能在网上查不到。
然而我已经超过26了，我之前也确实不知道有这么一回事。想请教一下大家这个还有什么补救方法吗？会不会因为这个就永久禁止入籍了？
Proving Good Moral Character If It's Too Late to Register
If you've passed age 26, it's too late for you to register for the Selective Service. Your chances of qualifying for U.S. citizenship depend on how many years have passed since you were supposed to register and how many years of good moral character you need to show. If you need to show five years of good moral character, then the easiest thing might be to wait until you are age 31 to apply for citizenship.
Proving That You Didn't Know You Were Supposed to Register
If you are eager to apply for citizenship before you turn 29 or 31 (as applicable), you may be able to show USCIS that you had no idea that registering was expected of you, and that you therefore didn't "willfully" fail to register, by submitting these along with your naturalization application:
a Status Information Letter from the Selective Service System
your sworn declaration, and
sworn declarations from people who knew you.
Obtaining a Status Information Letter
A Status Information Letter from the Selective Service simply states that you are over-age and therefore no longer required to register. However, you need to get one, because USCIS will refuse to look at the rest of your materials without it.
You can request the Status Information Letter from the Selective Service System website or by calling 847-688-6888.
Drafting a Sworn Declaration Explaining Your Failure to Register
Your sworn statement should offer reasons why you failed to learn about the Selective Service registration requirement.
If you attended high school in the U.S., you were probably told about this requirement, and will need to additionally explain why the information did not cause you to register. (For example, perhaps you heard about the requirement but believed it applied only to U.S. citizens.)
You will also have trouble claiming ignorance of the registration requirement if you got your green card either through the amnesty program in the 1980s or more recently, during or after the year 2001. In both cases, people were alerted to their registration obligations.
If possible, get letters from other people who knew you, particularly people in positions of authority, such as a high school teacher. The letters should support your explanation of what happened to result in your not knowing you were supposed to register.
你拿到绿卡的时候几岁？现在几岁？
当时23岁。现在28岁。
很有可能你已经被登记selective service了。如果你是在美国境内通过Adjustment of Status拿绿卡的，I-485表有一部分是如果你是男士在18岁和26岁之间，你允许uscis帮你自动登记。如果你是在美国境外通过Consular Processing拿移民签证的，我相信移民签证申请表也有一部分是你允许他们帮你自动登记的。你打电话去selective service system问一问。有可能在网上查不到。