Abstract: Aiming at the problems of wind and photovoltaic power curtailment and the lack of flexibility in the power system after the connection of the large-scale renewable energy power generation, a method of the flexibility evaluation considering the wind and photovoltaic power curtailment is proposed. Firstly, the uncertainty of renewable energy output at the demand side of the power system flexibility and the error influence of load forecasting are analyzed, and the demand for the power system flexibility is reflected by the net load curve; Considering the uncertainty of forced outage of the conventional thermal power units and the climbing uncertainty of unit output changes, then the conventional thermal power units at the supply side of the power system flexibility are randomly evaluated; Using the probability evaluation based on the probabilistic production simulation, and on the basis of obtaining the flexibility index of the power system, the impact of wind and photovoltaic power curtailment on the flexibility of power system is considered, and a new method of the flexibility evaluation taking into account the consumption capacity of renewable energy is finally proposed. The effectiveness of the evaluation method is verified by the examples of the IEEE RTS-24 bus system and the IEEE 118-bus system.