This invention relates to the technical field of TD-SCDMA mobile communication and specifically provides a TD-SCDMA communication system multiframe synchronization method and a device. wherein, the methods specifically comprises the following steps: carrying out wireless channel equalization to a baseband signal according to a sub-frame synchronization point to obtain a soft bit information flow;carrying out channel decoding to the soft bit information flow to obtain a hard bit information flow; carrying out CRC check to the hard bit information flow, if checking results are all zero, multiframe synchronization signals are output, otherwise the multiframe synchronization signals are not output. The invention also provides a TD-SCDMA communication system multi-frame synchronization device, comprising a downlink frequency pilot code correlation module, a public time slot demodulation module, a channel decoding module and a CRC check module. The invention improves the anti-interference ability by channel decoding, and utilizes CRC check to exclude the false alarm probability of the multiframe synchronization, thus greatly enhancing the accuracy probability of the multiframe synchronization.