In recent years, as the portal frame’s height toward higher and the span toward wider, the influence of wind vibration becomes more and more prominent among the portal frame structure. In the design of the portal frame, there are many different opinions on whether considering the impact of the vertical wind vibration to the portal frame. This paper taking a true engineering as an example, using finite element software to establish the solid model of the portal frame structure, selecting the junction of purlin and roof as a node of imposing vertical fluctuating wind load, we made numerical simulation analysis of vertical wind vibration. The simulation results will be compared with data of the internal forces and deformation under the average wind pressure. The results showed that: vertical wind vibration has a prominent effect to the portal frame and should be considered in the design.