Queuing is a common phenomenon in daily life. The theory of queuing provides theoretical basis and optimization scheme for queuing in real life. However, due to the limitation of time and space, the queuing problem in real life is not an ideal queuing model, and the field verification of the queuing model with losses consumes a lot of manpower, material resources and financial resources. In this paper, a queuing model with loss mechanism was established by using color Petri net. One-dimensional random walk model was improved and introduced into the queuing system to further reveal the principle of loss in queuing. CPN tools were used to simulate the model. By comparing the experimental results with the actual results, the correctness of the model is proved, which fully indicates that the model can well explain the loss of queuing system in real life.