In order to calculate the bending vibration frequencies of box girder bridges with corrugated steel webs， and taking a prefabricated box girder bridge with corrugated steel webs in the connecting line of Jingzhong airport in Lanzhou as the engineering background， a finite element numerical simulation and field test methods are used to study its dynamic characteristics. First， the finite element model of box girder bridge with corrugated steel webs is developed by using ANSYS software. The correctness of the finite element model is verified by field tests. Subsequently， the change rule of natural frequencies and mode shapes of box girder bridge with corrugated steel webs are analyzed under the influence of different parameters. The results show that the finite element model can accurately simulate the actual bridge structure. Compared with K-type and square-type， an I-type external intermediate cross-frame system can better improve the overall rigidity of the bridge. Diaphragms spacing has little effect on the natural frequencies of the bridge within the range required by the specification. The thickness of corrugated steel webs have a great influence on the torsional natural frequencies of the bridge， followed by that of bending vibration frequencies. The difference between the calculated values of natural bending vibration frequency fitting formula and ANSYS is from 0.23% to 1.89%， respectively， and the former accuracy is high. The research results can provide a reference basis for dynamic characteristics analysis of box girder bridges with corrugated steel webs.