As an effective complementarity to domestic A share market, H share market has played an important role in attracting foreign capital flows into mainland.Considering that H share market enjoys relatively more freedom of information and has greater and faster access to global news sources,the paper mainly researched on the discount between H share and A share. By constructing the model and proposing the proposition, our empirical test confirms our proposition about the factors affecting this discount both from the cross-section and time-serial data.