Builders hoist, also known as structure or construction elevator, is an indispensable piece of vertical transport equipment in high-rise building construction. And the material of the cage accounts for a large proportion of builders hoist, and the unreasonable distribution of the cage components will greatly cause material redundancy. In order to reduce the production cost of builders hoist and maximize the material utilization rate, the static analysis and finite element calculation of the cage of builders hoist are carried out by ANSYS Workbench, and the topology optimization and response surface method are used to carry out the secondary lightweight design and modal analysis of the cage. The results show that the optimised cage structure layout is more reasonable, meets the requirements of mechanical properties and strength, and does not resonate, and the mass is reduced by 489kg, with a weight reduction ratio of 40.75%, and the light weighting effect is remarkable.