Hi, I'm planing on travelling to canton fair through hong kong, do we need a visa to China. Thanks

You need to apply for an M type by submitting the following materials to the Commisioner Office of the Foreign Affairs Ministry: a valid pasport and a photocopy of its data page, a completed application form attached with your recent color photo, the original and photocopy of your entry permit for Hong Kong, and an invitation letter from the trade fair. However, you are not guaranteed to obtain it by yourself. TO play safe, you'd better find a travel agency to submt the application.