Pneumatic cylinders, as a long lifetime product, are used continuously under normal conditions. So Accelerated Life Testing is an important tool to get information quickly on lifetime which is achieved by subjecting the test cylinders to conditions that are more severe than the normal ones. This paper firstly analyze the failure mechanism of pneumatic cylinder, then based on the General Log-Linear relationship and Weibull distribution, describes a model for multiple stress-type accelerated life data analysis. The paper gives the parameter statistical method of the mode by using likelihood theory. Based on the test data from ALT of pneumatic cylinders which adopt four test stresses including air temperature, motion frequency, working pressure and operation velocity, the parameter of the model are fitted. According to the test data and the estimated model, the paper extrapolates the pneumatic cylinder’s lifetime information under the normal user level.