Trapezoidal corrugated web girder is a new-type welded structure with excellent mechanical property. Studies show that the geometric parameters of web have a great influence on basic mechanical property, but there are few studies on the influence of fatigue property. The trapezoidal corrugated web girder is modeled by parametric finite element modeling method. The inclined web folds and fatigue points of the weld toe at the south side are used as the fatigue weakness,and the equivalent structural stress range is used as the assessment parameter to evaluate fatigue property. The influence of geometric parameters such as the web thickness t,angle of inclination θ,bend radius r and wave height hr on the fatigue weakness are studied. Results show that the most critical geometric parameter influencing the fatigue property of trapezoidal corrugated web girders is angle of inclination θ,and the recommended range is between 27°and 37°in manufacturing. Other geometric parameters have little influence on the fatigue property of trapezoidal corrugated web girder,but this must be considered combining with practical manufacturing technology and the value of angle of inclination θ.