The rotor is a high-speed rotating part of turbocharger, which often bears high and low cycle fatigue load in operation. Its safe operation is particularly important. In order to obtain the high and low cycle fatigue life of turbocharger blade, the fatigue life characteristics were analyzed by changing the high and low cycle composite stress ratio and the high cycle frequency in a single composite fatigue load block, and the life evaluation model based on Miner's theory was established. Based on this model, the combined fatigue life of turbine blade at 160000r/min is 19094 times. Finite element analysis software was used to analyze the stress of turbine blades at the same speed, and the maximum values of low and high cyclic stresses and their crucial positions were obtained. Through the modal analysis and harmonic response analysis results of turbine blades, combined with the commercial software Ncode, the high-low cycle composite fatigue life of crucial parts of blades was obtained to be 19,664 times. The difference between the life assessment model based on Miner's theory and the prediction of high-low cycle life of blades by Ncode software is 2.89%, which can both reliably predict the fatigue life of blades under high-low cycle composite conditions. The solution process of NCODE software is weak in universality and complex in operation, while the life modification model based on Miner's Theory is relatively convenient to use and easier to be popularized and applied in engineering.