Abstract: An OQPSK modulation scheme used spread spectrum is proposed which is based on the Chinese medical band. The analysis is done under variety of interference, the simulation results indicate that this scheme has good performance of the broadband interference suppression, but is sensitive to the narrowband interference because of high false alarm rates of frame detection. A new frame detection algorithm based on twice delayed-autocorrelation is proposed, and it is verified that the algorithm exhibits better performance for narrowband and wideband interferences. The recording results of this paper can provide technical reference for standards development of wireless body area network standards. Currently, this scheme has been adopted in IEEE802.15.4n.