Clock synchronization is a major indicator of the distributed network test and control system. The precise time synchronization is also one of the core technologies of the network communication of test and control system. The paper illustrates the fundamental principle for clock synchronization under IEEE1588 protocol and concludes that its synchronized accuracy is influenced by the accuracy of time stamp and transmission delay jitter through analysis. An autoregressive clock drift model has been put forward in the paper in an effort to improve the time synchronization accuracy. It makes use of the Kalman filter to estimate the deviation and drift of the master and slave clock so as to offset it. The results of simulation indicate that the method can effectively ease the impact on time synchronization for time stamp and improve its accuracy of the test and control system.