what type of visa should i get to visit my Chinese boyfriend for 4 months?

It is hard for you to stay in China for 3 months, now he is just your boyfriend rather than husband, there is no legal document to prove the relationship. The L visa for family visit is not suitable, once you have the marriage certificate, you can apply L visa for family visit and asks for 4 months stay duration.

Now, you can only apply for a L visa for sightseeing, the requirements are:
your passport and its copy
one passport photo
filled visa application form V.2011A
A copy of the round-trip plane ticket
invitation letter with a copy of your boyfriend's Chinese national identity card
the old China visa sticker

Maybe you only get a single entry L visa with 30 days or less stay duration

hi thanks for answering my question..
how about getting L visa and then i will just renew my visa in china?is that possible?so i can stay with my boyfriend for 4months?and if ever how much the renewal fee in china?and is there any requirements do i need to submit there?thank you againso i can stay with my boyfriend for 4months?and if ever how much thehow about

If you hold a L visa to enter China, you can apply for visa extension (renew visa) when your L visa will expire. The L visa can be extended twice only, 30 days for each time, if you successfully get the two extensions, you can stay in China for 90 days.

thanks mr. jim for answering..i just want to know now how much is the renewal fee (visa extension) in china?and what are the documents do i need to submit there?thank you

The renewal fee is 160 RMB, you need to submit your passport, one passport photo, the copy of China visa, the accommodation sheet issued by a local police station or a hotel and financial certificate to the visa officer at the exit-entry administrative bureau when you apply for visa extension. You can ask your Chinese boyfriend to go with you, He speaks Chinese, he can help you to communicate with the visa officer.

but what if m going to live with my boyfriend while staying in china?do i need to pass those documents?i mean the hotel accomodation sheet and everything?thank you

If you live with your boyfriend while you are in China, you need to show an invitation letter from him, in which you are supported accommodation with his address and his other information like ID Number, etc. Your passport, one passport photo, the copy of China visa are still needed. Financial proof is necessary to be prepared in advance.