Aiming at domestic researchers deal with the study of crane lightweight is not intensive, taking the 160T bridge crane car for example, by making use of SolidWorks and Ansys software, based on iSIGHT optimization design platform, integrated the parametric design system, realizing the outer frame of the trolley frame based on method of multidisciplinary optimization design ,constructed the general software running environment of the entity model which needs finite element analysis and on this basis needs further study of structure optimization design, determined the plate thickness size of the main beam structure which can make the trolley frame to be lightest, achieved the objective to reduce trolley frame quality of the bridge crane, and provides theoretical and practical examples basis to realize the rapid and effective lightweight design of the crane to some extent.