You need a tourist visa to enter Thailand.
Visa Office of the Embassy of Thailand in China
Address: No. 21, Guanghua Road, Chaoyang District, Beijing.
Tel: (86-10) 8531-8768
Fax: (86-10) 8531-8737
Processing times: 09:00-11:00 from Monday to Friday
Receiving times: 14:00-16:00 from Monday to Friday (The embassy is closed on national holidays. Please check the notice on the official website for closing times.)