When large amounts of wind power plants are integrated in power system， the impact of wind power on the reserve demand becomes a very important issue. This paper discusses the possible solutions regarding reserve demand considering the wind power uncertainty. A probabilistic method is proposed to estimate reserve capacity caused by wind power. Based on a primal dual path following interior point method， a secondary reserve optimal power flow approach is presented. Simulation results on the IEEE 39 system show that the proposed method can consider the impact of wind power on the secondary reserve efficiently， and is very practical.