The security of the upright shore-to-ship power supply system will be significantly affected when its cable is pulled up by extra load. To solve this problem，combined with the actual engineering needs of shore-to-ship power supply system under the large water level difference of the Jiuzhou River anchorage in the Three Gorges reservoir area，a connection box lifting device is designed which consists of electric box platform and lifting mechanism. The electric box platform can run up and down the track，and its main structure is truss structure.The lifting mechanism consists of hoisting gear and pulley block which is used to drive the electric box platform. And then，the truss structure is modeled and analyzed using the 3D BIM software Inventor，and the traction of hoisting gear is calculated. The results show that the truss structure can meet to requirements of the strength，the traction can meet the requirements of the hoisting.