Comparison and impact analysis of different risk dispatch strategies of new power system can help dispatchers get more detailed operation information, so as to promote their practical skills when making decisions about risk dispatch strategies. First, Copula theory is used to build the probabilistic distribution of forecast error given a specified forecast value, and multiple scenarios can be obtained by Monte-Carlo sampling. Second, three different risk dispatch strategies are built and compared, which are two-stage stochastic optimization modelling, chance-constrained approach and deterministic models, and then derives and analyses day-ahead electricity prices based on Lagrange multiplier method. Last, the example analysis shows that the results of other two models can be covered by setting different confidence levels in chance-constrained approach. The two-stage stochastic optimization model is rather conservative, while the deterministic model is rather aggressive. It also shows that it is prone to curtail new energy power during low-load periods in a high proportion new energy power system.