This paper describes a new method of frequency estimation in cell search of TD-SCDMA system. Before identifying the scrambling code and Midamble code, using part of sync-dl code data for frequency estimation; and before controlling the multi-frame synchronization, using part of Midamble code data for frequency estimation. Also these two sets of estimation can be done under the same frequency estimation structure by using the same 64 chip input in order to save hardware resources. The simulation results show that even with certain sample differences, this method can keep the residual frequency differences within 0.05 PPM by averaging out the subframe or by IIR filtering to satisfy the requirement of frequency estimation for TDSCDMA system.