Abstract: The instantaneous frequency of signal can be estimated by time-frequency analysis, the estimation performance is inferior in the low SNR, but the variational trend of the signal frequency is well-regulated and is surrounded the true frequency. So, the estimation method of signal frequency via time-frequency analysis and frequency model is presented in the paper. Firstly, for the TF analysis can highlight the TF distribution of signals, the estimated instantaneous frequency(EIF) of signals is got by detecting the maxima energy positions of TF energy signal; secondly, using the a priori knowledge of smoothness and continuity of the IF, the model of the IF estimation is analyzed, and the trend of the IF is estimated via maxima probability principle, then the initiative position of the filter is found; finally, the EIF is filtered and smoothed through kalman filter and kalman smoother, then the precise estimation of the signal IF is achieved.