Abstract: Sometimes the high-accuracy system time synchronization is needed among the individual subfunction modules of a large system to accomplish system function closely.Thus,a novel high-accuracy system time synchronization method based on dataless pseudo-random code is proposed.And,by use of the non-equal sampling technique,the time resolution abstractly approaches 15.3 ps among the discrete subfunction modules.The simulation experiment results show that under -20 dB SNR(signal noise ratio) environment,the system time synchronization accuracy(standard deviation) approaches 0.066 ns whereas under the 0 dB SNR environment,it approaches 0.040 ns.