Abstract: In order to meet the demand of wide-area time synchronization for the rapid development of smart grid,a new widearea time synchronization method is proposed,in which satellite clock and network clock are mutually spare.Based on an analysis of the error characteristics of satellite clock,crystal clock and network clock,the high-precision synchronous clock timing method combined with satellite clock and crystal clock is studied,and a message path delay improvement algorithm featuring IEEE 1588 protocol network clock is proposed. On this basis,a distributed autonomous wide-area time synchronization scheme focused on high-precision synchronous clock and network clock is put forward.The simulation results show that the wide-area time synchronization scheme can realize accurate and reliable time synchronization of the time nodes in the wide-area network while meeting the time synchronization requirement of the smart grid.