Asymmetric information is the key point of contract theory and the basic reason of contract design. It is commonly accepted that high-tech uncertainty causes asymmetric information in the venture capital investment, and lack of some specific knowledge leads to incomplete information. In fact, this asymmetric information doesn't come from outer-uncertainty of high-tech but inner-uncertainty of human capital, including uncertainty during input, output and withdrawn of human capital. Therefore, contract design of venture capital should be based on the uncertainty of human capital. In this paper, we are trying to give a theoretical explanation to the contractual arrangements of staged financing, surplus of property rights and control rights during the venture capital cycle.