Abstract: An accurate synchronous condenser model is the foundation of system analysis, operation and control. In order to obtain accurate synchronous condenser parameters to meet the increasingly refined simulation requirements of the power system, an identification method based on time-frequency transform is proposed. Based on the sixth-order practical model of synchronous condenser, the differential equations in the time domain are converted into algebraic equations in the frequency domain. After eliminating the transient EMF and sub-transient EMF, the decoupled d-axis and q-axis transfer function is obtained. Based on the measured data, genetic algorithm is used for the correction of transfer function. After the identification values of the coefficients are obtained, the practical parameters of synchronous condenser can be identified according to the relationship between the practical parameters and the coefficients of the transfer function. Finally, the dynamic process simulations are carried out in PSD-BPA to verify the rationality of the identification results.