Photovoltaic(PV) power generation is one of the important ways to ensure that our country's energy security and realize the sustainable development of energy, but carrying on the investment risk assessment has become the focus of the difficulty and risk decision. Firstly this paper established its risk evaluation index system according to PV power project investment risk characteristics, and then used the improved multi-level analytic hierarchy process analysis method and through the PV power project example for risk weight calculation. Examples show that investment decision-making risk PV power is mainly influenced by the output volatility and government support two factors. So, PV power projects investment should keep the project in the solar ene rgy resources abundant geographical environment ,then choose highly conversion efficiency PV cells and the highly quality of PV power generation components; The department of energy and the government need to develop more effective policies and measures to increase PV power industry support.