Abstract: Based on Monte Carlo method, the impact factors of the importance of exception handling module were proposed,which include the importance of its protected areas and its steady-state failure rate. The former is calculatecd,based on bayesian theory,while the latter using the ergodicity in Markov chain. The ctuantitative analysis tries to offer an effective solution. According to the result, designer could pay more attention to the specific module.

Key words: SOA, Software reliability, Exception handling, Monte Carlo method