For the tracking problem of radar working state by electronic reconnaissance system, a radar working state tracking method based on fused hidden Markov model is proposed. First, the radar working process is modeled as a hidden Markov model by this algorithm. Second, by recognizing the reconnaissance radar phrase sequence, the tracking of radar working state is realized on a single platform. Finally, the DS evidence theory is used to fuse the recognition results of multiplatform to realize the multiplatform fusion tracking. The recognition rate of the algorithm is simulated, and the simulation result shows that the proposed algorithm can improve the tracking accuracy of radar working state under error observation. When the error rate of observation is 20%, the tracking accuracy reaches 93%.