In order to predict the frequency of the frequency-agile radar of rotary-tuned magnetron,the transition vector of frequency variation trend is defined.Then,the nonlinear equation set for estimating the tuning parameters are transformed into linear equation set.Finally,a frequency prediction method based on the least squares estimation is proposed.Compared with the existing methods,the proposed method has lower requirements on the data quality,and is more adaptive to the complicated application environment.Experiment results based on the measured data indicate the effectiveness of the proposed approach.