According to the efficiency of repairing imminently faulty bus in the city

this paper establish the model for the process of repairing the fault bus based on the Stochastic Petri nets (SPN) .Since the Stochastic Petri nets and the Markov chain is isomorphic

the stable state space of the repairing model can be gain.Then the probability of each state will be calculated.The analysis for the utilization rate of the every repairing step and the time attributes of the every steady state can be given.These can provide the relevant evidence for improving the efficiency of repairs.At last an example is given to verify the availability of the modeling and analysis based on SPN.The efficiency of fault repair will be improved through enhancing the efficiency of some repairs step.