A new TTCM direct series spread spectrum system scheme was put forward. It is based on the signal sets through expanding spread spectrum series phase. This scheme can increase the minimum Euclidean distance and improve the BER performance without any increase of the signal power, slowdown of the information speed or change of the modulation mode. The simulation results show that the proposed system can achieve 13dB coding gain more than the ordinary TCM system while increasing no sensitivity to initial phase error or the phase noise of the carrier wave.