The invention belongs to the field of telemetry, and in particular relates to a method for expanding the frequency offset estimation range of a telemetry coherent receiver. Under the PCM-FM system, the invention uses the frequency estimation module to estimate the frequency offset of the PCM-FM intermediate frequency signal, assists the synchronization of the synchronization module of the original MSD system, thereby increasing the frequency offset estimation range of the MSD system. The invention uses a simple complex multiplication-accumulation circuit, which can expand the frequency offset estimation range of MSD demodulation by tens of times, thereby extending the frequency offset estimation range of the MSD system. The frequency offset estimation range is wide, the frequency offset estimation speed is fast, the demodulation performance is good, the circuit is simple, the calculation cost is small, and the work efficiency is high. The present invention can be applied to PCM-FM system telemetry receiving equipment in high-frequency and high-noise telemetry task environments such as missiles and rockets, greatly reduces equipment complexity, and effectively improves the performance of the PCM-FM system telemetry receiver.