This article analyzes the design of a variable-height simply supported steel truss bridge based on an actual project. It includes its basic situation, introduction to variable-height simply supported steel truss bridges, key design points of such bridges, and finite element analysis of the design effect. The analysis shows that for such bridges, reasonable main structure design and node design are the keys to determining the overall design idea, and through the reasonable application of the finite element analysis method, the design effect can be scientifically determined, providing a reference for the subsequent structural design of such projects.