Abstract: Because lithography is a precision machining, it has higher requirements for the flatness of grating ruler placement platform in working condition. Under the action of self weight and compression force, the structure will have self deformation, which will affect the machining accuracy. This paper takes a long grating precision photolithography duplicator produced by a company as the research object, uses the numerical simulation method to import the threedimensional model established by SOLIDWORK software into ABAQUS finite element analysis software, and carries out static and modal analysis on its structure. Based on the numerical simulation results, the structure is improved, so as to improve the overall structural stability and place the platform plane The homogeneity of.