Considering the change of the main unstable equilibrium point caused by different generator tripping measures, a generator tripping strategy based on sensitivity is proposed. First, the part of the transient stability margin related to the controlling unstable equilibrium point is extracted, and then the modified equation of the generator tripping amount and the controlling unstable equilibrium point is established, and the change of the controlling unstable equilibrium point is determined by the Newton-Raphson method. The sensitivity of the transient stability margin of the system to different generators is calculated, and finally the generator tripping strategy is formulated according to the sensitivity. The simulation results on the New England 10 machine 39 node system show that the sensitivity of this strategy is more accurate than that of the cutting strategy without considering the change of the controlling unstable equilibrium point. It can effectively reduce the total generator cutting amount. At the same time, the solution steps of the strategy are direct and clear, which avoids the tedious calculation process and saves calculation time. This work is supported by the Key Project of National Natural Science Foundation of China (No. 51637005).