If I got a green card based on marriage 10 years ago and green card is expiring, what documents do I need to bring when I apply for a citizenship?

You can apply for naturalization as long as the green card is still valid and you would submit a copy of that as part of your application.

Because your N-400 for citizenship application is being filed well outside the 3 year anniversary of your becoming an LPR, your marriage or lack thereof is not relevant.But, as a general rule, when it is considering your application for citizenship, it is still permissible for DHS to inquire about most every aspect of your life including your marriage, if such inquiry is meant to ant to gauge your fitness to become a US citizen. Therefore, although, not technically required, if the record shows that you are not a good husband or that you fail to support your dependents such as your wife or children, then, such determination reflects poorly on your good moral character, which is one of the requirements for admission to US citizenship. If your marriage is failing or if you are separated, you can say so if asked by the naturalization examiner. It will not detract from your eligibility to become a US citizen.

You do not have to provide proof of the marriage since you are applying after more than 5 years of LPR status.

You should contact an experienced immigration attorney to guide you through the N-400 naturalization process which, on average, will take a year or more. Be sure to renew your currently expiring I-551 green card within 90 days of its expiration even if you are filing for citizenship status.

You only need to bring for your interview what they asked you to.

It is always good to bring documents to the interview that prove the marriage upon which you received your lawful permanent residency was, and in your case, still is a valid marriage. Bring your taxes, deeds or rental agreements, bank statements, insurance (medical, car, life, etc.) and any other documents that show the validity of your marriage. It will not be the primary focus of your interview, but many officers want to discuss the validity of the basis upon which you originally received your green card. Having some proof on hand will keep your interview focused on the naturalization requirements, and not the validity of your marriage.