Abstract: The fuzzy comprehensive evaluation model of the welding quality is introduced based on the principle of fuzzy mathematics.According to GB3323-2005 standard,the weld quality classification factor set,the evaluation set and the weight vector are established,and fuzzy comprehensive evaluation is completed.In accordance with the principle of the largest degree of membership,the level of weld quality is determined,the livability of S-N curve have objective choice,so that the quantity of weld fatigue life is amended.Finally,by BS7608-1993 fatigue design and assessment of steel structures standard and actual example,the fuzzy evaluation model based on the quality of the weld fatigue life evaluation process is explained,and the results show that the model is feasible,the calculation results are reasonable.