This paper analyses completely the general network models and network structure patterns currently and discusses their characteristics and implementation approaches. The paper also summarizes similarities and differences of these network models and their merits and disadvantages. Based on the above research, the paper puts forward the thought of system design for test system based on network .The test system has changed from the previous concentrative mode to the distributive mode which is on the network and it should develop into the system with the qualities of openness, inter-operability, networking. The networking test nodes should possess the qualities as extensibility and communality. This paper also discusses the software design of the test system model based on the network and puts forward a kind of design plan for the structure of the networked test system that adopts the hierarchy plus the functional interface. The software design of networked test system closely encompasses the thought of modularization, generalization and standardization.