In order to assess the short term operational risk of the power grid under the ice-covered galloping environment and ensure the normal operation and maintenance of transmission lines, a short-term risk assessment method of power grid considering galloping prediction of transmission lines is proposed. It seizes two factors that determine the fault risk degree:the fault likelihood index and the system consequence severity index, which can grasp the impact of galloping on the short term operation of the power grid from an overall perspective. The fault likelihood index is comprehensively determined by the galloping prediction probability calculated through a BP neural network and the historical galloping level of a region which is divided by the frequency method. The system consequence severity index is calculated according to the conductor overload degree and bus voltage out-of-limit degree after power flow transferring. Taking the galloping data of Henan power grid as a case study, the results indicate that the proposed method can effectively evaluate the short term operational risk of power grid. The galloping early warning and risk assessment results can provide decision-making support for power grid dispatchers and transmission line operation staffs, help them adjust operation mode of power grid and (or) implement anti-galloping assignment of transmission lines in advance, to reduce the impact of transmission line galloping on the security operation of power grid. This work is supported by National Key R&D Program of China (No. 2016YFB0900600) and Major and Basic Project of Foresight Science and Technology of State Grid Corporation of China (No. SG20141187).