Abstract : Since the appearance of computers network until the use of the internet many types of LAN were applied according to the topology or to the way of exchanging the information (access method). To get the better and suitable ways, the need to study the performance of LAN was appeared in order to know the network performance through measuring the time of information receiving, to know which type is suitable for a specific job and place. The Token Ring LAN considered as one of the best methods of LAN because of its access method as a controlled access method and its high reliability for use of double Ring. Petri Net theory is generally used to model the computer system behavior. A Petri Net model is used to represent a Token Ring network and give a complete analysis to the Token Rotate Time TRT and the parameter on which it effects, on the basis of proposed PN model. The Token Rotate Time is the time token transfer from a node to another and back again to the same node which means the time of data transfer.