The integration of wind power will have shock on the stability of the power system. In view of the uncertainty of wind power, proposing a probabilistic load flow algorithm calculating the comprehensive vulnerability index of the grid branch. The improved branch betweenness is proposed to describe the structural vulnerability of the branch, introducing weighted power flow entropy to describe the operating state vulnerability of the branch. Then, weighted the two to form a comprehensive vulnerability index, evaluating the comprehensive vulnerability index of the branch. On this basis, probabilistic load flow is used to calculate the comprehensive vulnerability of the branch in the case of wind power integration, that is, the probability comprehensive vulnerability. Based on the probabilistic comprehensive vulnerability, the probabilistic comprehensive vulnerability entropy index is proposed, which provides a basis for the selection of grid nodes of wind power integration. Simulation results on the IEEE 39-bus system indicate that the proposed method is reasonable and effective.