Time synchronization in Wireless Sensor Network (WSN) is as much important as in wired networks or ad-hoc networks, as well. So, various Time Synchronization Protocols for a WSN have been proposed because WSNs have the critical resource constraints and characteristics, other than the other networks. It is not easy, however, to evaluate the performance of these Time Synchronization Protocols because they are designed for different goals and implemented in different ways. In this paper, we propose a performance evaluation approach for WSN time synchronization protocols. And we also evaluate and analyses several representative time synchronization protocols developed in WSN. It is shown that the proposed performance evaluation approach for WSN time synchronization protocols is useful through simulation.