Abstract: During the service life of the excavator crawler track link, failure problems such as cracks and chipping occur. A comprehensive failure analysis of the track link is carried out through tests of chemical composition,hardness, microstructure, fracture morphology, finite element, etc. The results show that the cracks in the track link are fatigue cracks, and there are stress-concentration areas in its structure. Through dissection analysis, it is found that the tempered grain size and the martensite structure in the hardened area are relatively coarse, while there are no obvious abnormalities in other inspection items. Based on the analysis results, design optimization is carried out to avoid stress-concentration areas. Moreover, the matrix grain size is improved by optimizing the quenching and tempering process, and the martensite structure is refined by improving the tread hardening process. Through the above improvement measures, the comprehensive properties of the track link, such as strength, toughness, and impact resistance, are enhanced, and the failure problems of cracks and chipping of the track link are significantly improved.