What kind of Visa to apply for my route of Hkg -Guangzhou-Hkg -Guangzhou-Hkg

Dear Sir ,

Firstly , I going to Hong Kong by flight form Yangon .Two days after I will leave for Guangzhou to see suppliers at there for two day before Canton fair and after back to Hkg .
About three days after I will leave again to Guangzhou for Canton fair maybe same days or next day will back to Hkg again. Thanks in advance .