i live in china , i want to invite my son to visit me for travel for 1 month,how to apply visa

Hi, you need to give your son an invitation letter. Then your son still need to prepare the following documents:
1) Application Form with recently-taken color photo glued or stapled on.
2) Valid Passport and a copy of its information page .
3) The original and copy of the Kinship Certificate or the Birth Certificate and the Marriage Certificate.
4) Personal Written Statement (Covering Letter,with details as follows: A. name of the scenic spot; B. name, address and contact number of the inviting(contact company or person).
5) Other documents required by the Chinese Embassy or Consulate-General.

With the above documents, he should go to the Chinese Embassy or Consulate General to apply a L visa for family visit.