Abstract: To create performance models of complicated systems,object-oriented modeling methods based on POOSL were proposed.The modeling process was divided into three stages:object-oriented system analysis,model design and model realization.Statechart diagram,sequence diagram and class diagram were applied in the modeling realization stage.Based on the object-oriented modeling technique,the performance model of IEEE 802.11 MAC protocol was built using POOSL.Through the simulation of the model,the influence of the parameters such as minimum contention window and number of active stations on the performance metrics such as valid throughput and average frame delay in ad hoc network were given.Simulation results show that the object-oriented modeling technique can be applied to performance modeling effectively.