Malaysian passport, apply for Chinese Visa in Thailand

Seah, you should apply for it from the CVASC. The required documents include your passport and copy of its data page, the filled-out application form attached with a passport-style photo, your valid entry permit to Thailand and an invitation letter from your trade partner in PRC. And then submit your application to the CVASC to apply.
A multiple-entry business M type for 6 months costs 2700 baht, and a multiple-entry business M type for 12 months costs 2800 baht.