Composite girder bridges with Corrugated Steel Webs (CSWs) have won increasing popularity among bridge designers owing to its exceptional mechanical properties. The extant literature focuses on the static and dynamic performance of girder bridges with CSWs, there is limited research on the mechanical performance of such structures under high temperature. The mechanical performance of composite beams with CSWs undergoes degradation under the influence of high temperatures during a fire. By conducting local fire simulation in Fire Dynamics Simulator (FDS) and finite element (FE) thermal-mechanical coupling analysis, this study examined the differences in shear performance between the three-span continuous and continuous rigid-frame beams with CSWs, under exposure to fire at the side span and middle span, respectively. This study discovers that the shear stress on the continuous and rigid-frame beam is disorderly distributed in the fire-exposed region, and the shear stress on the CSWs is no longer uniformly distributed but exhibits violent fluctuations. Additionally, at the fire-unexposed spans, the shear stress on the continuous beam increases by several multiples, whereas the shear stress on the rigid-frame beam experiences minimal change. This study provides a reference for further optimizing the fire performance design of composite beams with CSWs.