How long will it take for relatives to immigrate to San Francisco to get a green card?

Your boyfriend got a formal green card.

After he returns to China to marry you, he will go back to the United States immediately and apply for immigration for you.

There are only a few months before the date of applying for a green card spouse. If it goes well,

In less than a year, you can come to the United States through an interview, which is also a landing green card.

However, your spouse must have a formal job and have a tax return for three years.

His income will surely guarantee you,

He can't do this. He has to find a joint guarantor. There are some troubles.

But it can also be solved

When he applies for your immigration, if he doesn't know anything, find an immigration lawyer from China to help you in the United States.

You will save a lot of trouble, just provide the documents required by the lawyer.

Note: You are looking for an American lawyer, not China's!

As for marriage, he is still a citizen of China, and marriage with a citizen of China is the same procedure.