The invention relates to a method of identifying sensitivity in damping ratio of leading electromechanical mode of a power system and belongs to the field of crossing techniques of dynamic stability analysis and power generation planning for power systems. The method includes: acquiring active power and dynamic response noise data of multiple generators in the power system in real time, identifying to obtain a damping ratio of the leading electromechanical mode of the power system, establishing a multiple linear regression model for the active power and leading electromechanical mode in multiple generators, and solving the model to obtain the sensitivity in the damping ratio of the active power to leading electromechanical mode of the multiple generators in the power system. The method has the advantages that independence on power system offline models is avoided, the sensitivity can be identified by online operation, the problems that modeling difficulty and high calculation amount occur in the process of solving the sensitivity in the damping ratio of the leading electromechanical mode of the large-scale power system by the traditional method and numeric calculation problems occur in the process of solving the derivative Jacobi matrix by the traditional method are solved, and the sensitivity calculation results provide basis for the analysis on stability of the power system.