Abstract: To enhance and evaluate the reliability of laser ignition systems,reliability model of laser ignition system was established by using GO methodology. The results of reliability analysis including minimal cutset of the system gotten by using GO methodology qualitative analysis and reliability of laser ignition system calculated by GO methodology quantitative method were carried on. Reliability parameters of various modules were predicted by using component stress method under the mission profile of non-working state for 5 y and working state with working time of 1 h. Compared with the results of FTA and Monte Carlo simulation,the applicability and the accuracy of reliability analysis of laser ignition system based on GO methodology are verified.