Abstract: The development period of lithography is long and the structure is complex, In view of the lack of systematic and effective evaluation methods for reliability work level of lithography machine at home and abroad, Based on the research of the development process of lithography and reliability project, a reliability index model and corresponding evaluation system for complex system lithography are proposed. It mainly includes reliability design, material optimization, reliability test, Aero-engine failure and field reliability data for reliability work level evaluation. The example shows that the index can be used to evaluate the reliability of the lithography objectively and guide the enterprises to improve the reliability continuously, so as to improve the efficiency and scientificity of the reliability system management of the lithography.