The actual value of wind power output varies randomly around the predicted value, thus, the randomness of wind power output should be considered in the power flow calculation. This paper proposes an optimal power flow calculation model based on scenario analysis of the wind farm connected to AC grid by VSC-HVDC, which can achieve secure operations and economic dispatch. The minimum total cost of thermal power plants is taken as the objective function of the model, and the adjusting range of active power output of thermal power plants under the forecasted wind power scenario and sampling scenarios is considered as constraints. Afterwards, the model is solved by utilizing interior point method. The calculation results show that, although the total cost of thermal power plants is increased after introducing sampling scenarios, the requirement of the capability of thermal power plants that can quickly adjust the randomness of wind power output is satisfied, thereby, the safety of grid operation is guaranteed.