Abstract: The precision time protocol (PTP) improves the clock synchronization accuracy greatly and makes sensors, actuators and other terminals share unique time reference, which assures clock synchronization quality of different terminals. This paper puts forward a typical network topology in wireless distributed measurement system, and introduces the work process of PTP. The improvement of PTP clock synchronization adjust algorithm is analyzed. The clock synchronization accuracy of tree network topology is presented through simulation in MATLAB. The PTP clock synchronization offset can be reduced significantly with the implementation of drift estimation and skew compensation in tree network topology.