Abstract: This paper introduces the important role that the high precision monitor system of the time synchronization device to the power system stable operation, and analyzed a lower-cost method to make the high precision synchronization device, and introduces the methods to pick out two important moments in the process of calculate time monitoring, and to suppression of network pressure in the inexpensive system, and carry out the actual test, to prove that the time synchronization device can be both inexpensive and high precision in the same time.