Abstract: To address the fatigue cracking phenomenon in the connection weld between the upper flange and the web of steel crane beams， a statistical analysis was conducted on actual engineering cases involving such fatigue cracking. Taking a crane beam from a steel plant as the research subject， the rainflow counting method was used to measure the equivalent coefficient of underload effects， and the strain time history and statistical results of stress cycle counts are obtained. Based on finite element models under different eccentric loads， the stress distribution in the crane beam under fatigue loading with varying eccentricities was compared and analyzed. Additionally， the fatigue strength of the crane beam under different web thickness conditions was verified. The results indicate that eccentric loading adversely affects the fatigue performance of steel crane beam webs. Increasing web thickness significantly reduces the shear stress level in the web and enhances the overall fatigue strength of the beam. In future fatigue design of steel crane girders， eccentric loading should be taken into account， and it is recommended to moderately increase the web thickness.