CHINA REQUIREMENTS TO MARRY IN THAILAND
China does not provide affidavit outside China,
China citizen much normally get the permission from their
local district in China and have it translated and stamped by
a Thai consult in China as being a certified translation of the
document or get a certified translation from the Thai embassy
in China. Before the Ministry of foreign affairs accepts the
documentation as official, or the Thai government marriage registars
will most likely refuse to approve your application.
Check here for legal requirements to marry in Thailand for
Chinese in Thailand on the China
embassy Website