The invention discloses an evaluation simulation system and evaluation method for theoretical output of an integrated wind power plant. The system comprises an information layer, an environment layer, a wind power plant layer, an evaluation layer and a database. The information layer is used for collecting information data from the internet and gathering the information data in the database to be called by the other layers. Information in the information layer, the environment layer, the wind power plant layer, the evaluation layer and a model parameter correction and modification system is read, stored and inquired by the database. The environment layer fuses the information data obtained from the information layer and establishes an environment model. The wind power plant layer comprises a wind turbine unit output analysis model and a wind power plant overall output model. The evaluation layer is used for establishing a wind curtailment amount model of a whole wind power base and evaluating the wind curtailment amount model. Through establishment of a simulation system platform, safe and economic operation of a wind power generation electric system is facilitated, the prediction result of wind power output can assist in power grid dispatching operational control decisions, and the stability of a wind power generation power grid is improved.