should I apply X1 visa to cover all my time stay in China and what kind document do I need ?

Hi, you can apply for a tourist L for summer camp with an invitation letter from China. But for your study from September/2014, you have to leave and apply for a student X 1 type. I am not sure if you will do the registration with the Zhejiang University after entry or not, because X1 is issued with 30 days only as the duration of stay. That means you have to get a residence permit within 30 days after entry, otherwise, it expires and you have to leave China.