Wide area measurement system (WAMS) is strict with real-time performance, and communication delay has great impact on real-time performance. Communication delay is an important part of WAMS delay. Its indeterminacy makes it important and difficult to study communication performance of WAMS. This paper establishes models of communication equipment, communication services and communication network topology of WAMS. According to these models, this paper gives three types of scene simulation, including static operating condition of power system, fault operating condition of power system and fault operating condition of network equipment. From this, the paper gets communication delay of WAMS in different operating condition to evaluate and analyze the current situation and bottleneck of WAMS. All above not only provide new method to research and analyze WAMS, but offer reference opinion to planning and construction of WAMS. This work is supported by National Natural Science Foundation of China (No. 51577073) and Natural Science Foundation of Guangdong Province (No. 2016A030313476).