Phased array radar (PAR)is an important part of modern military electronic equipment. Multi-channel data synchronous acquisition is a key technology that needs to be solved when receiving and processing PAR signal. Traditional parallel acquisition systems have low channel integration and limited transmission rate, which does not meet the trend of miniaturization, high bandwidth and deterministic delay of data acquisition systems. This paper briefly introduces the principle of phased array radar, and principle of JESD204B protocol for synchronous design. Based on the full understanding of the principle, this paper analyzes the key technology of synchronization using this protocol and designs a multi-channel data acquisition board. The board realizes single system synchronization through strict routing, and achieves multi-system synchronization using the master-slave system design. The test results show that the data acquisition system using JESD204B protocol can effectively realize multi-channel data synchronous acquisition.