The multi-channel mode of phased array radar increases the degree of freedom and improves performance of the system. To solve the synchronization problem of the radar， a multi-channel synchronization method for phased array radar is proposed. It uses the synchronization trigger mode for single clock chip. The delay values of multiple synchronization signals of the clock chips are adjusted accurately. An adaptive sample window center adjustment method is proposed for multiple high speed analog to digital converters. This method is used for actual radar products. Test results have demonstrated the effectiveness of the approach to implement multi-channel synchronization for phased array radar.