Update design theory, improve reliability and extend service life. The United States, Britain, Japan and other countries to promote the theory of finite life design, to replace the traditional infinite life design theory and method, and the fatigue damage accumulation theory and fracture mechanics, the finite element method, optimization design, computer control of electro-hydraulic servo fatigue test technology, the advanced technology such as fatigue strength analysis method is applied in hydraulic excavator, the strength of the research to promote the quality of the product efficiency and competitiveness. The dynamic design analysis method for dynamic strength assessment is proposed in the United States. Japan has developed the strength assessment procedure for hydraulic excavator components and developed the reliability information processing system. Under the guidance of the above basic theories, by means of a large number of tests, the research period of the new products is shortened, the process of replacing the hydraulic excavator is accelerated, and its reliability and durability are improved. For example, the hydraulic excavator has a transfer rate of 85 to 95 percent and a service life of more than 10,000 hours.