The current domestic large temporary works mainly adopt steel structures for the recycled use.As the load on the large temporary works become heavier,the steel structures would cost more.Therefore,it is a challenge to ensure the safety of the structure and reduce steel consumption as far as possible.This article describes the design of the girder upgrading gantry for a temporary dock project of HZMB.Adopting different structure forms and making full use of the existing materials,we finally determine the reasonable structure of the gantry.