Am a foreigner in russia, i want to visit my brothers in china. what are the requirements for me?

You can either apply for a tourist L type visa or a family reunion S type, depending on how long you want to stay in PRC.
If the stay is not too long, maybe shorter than one or two months, L type is a better option.
If the stay is longer, you can apply for an S type.

Both types need you to submit passport, passport copy, application form, passport size photo, an invitation from your brother, and the original and photocopy of residence permit in Russia. Besides, S type requires a relationship certificate and a copy of your brother's passport and residence permit.