In order to calculate the fatigue life, lifting or unloading position, lifting weight and load mobile line of crane with automatic acquisition device were recorded on spot. Probability distribution model and its characteristic parameters of lifting weight and lifting or unloading position were analyzed with goodness of fit test. The random samples of the load spectrum parameters for the cumulative fatigue were also calculated with Latin Hypercube Sampling. Dynamic simulation model of crane metal structure was formed. Dynamic load function that dynamic load changed with time was also established, from which the stress spectrum through structural dynamics analysis in fatigue calculation point was acquired. Based on then above calculation, the remaining fatigue life of the prototype is 38 years.