Takes a storehouse 32 t×165 m bridge crane as the research object, a new method of obtaining the whole stress spectrum on online monitoring system was put forward. On the basis of the whole stress spectrum, according to the material PSN curve, considering the fuzziness of fatigue limit, the fatigue life of the girder was estimated using fuzzy accumulative damage theory.The result shows that the left life of bridge crane is 388 years, it provides a reliable for cranes longtime use and maintain.