Inclusions are typical discontinuous defects, those defects significantly reduce the local mechanical properties of castings during solidification, and play a strong role in inducing and enhancing hot tearing in alloys. Based on the coupling characterization of micro solidification morphology and macro inclusions, this paper proposed a construction method of heterogeneous model containing multi-scale information, and carried out dynamic analysis on the evolution process of stress field at the end of solidification, so as to investigate the influence mechanism of inclusions on the initiation and propagation of hot tearing. The results showed that inclusions and their local content significantly changed the stress field at the end of solidification, which easily resulted in local stress concentration and induced crack source in defects area. During the crack propagation, nearby inclusions greatly reduced the propagation resistance and promoted the formation of hot tearing, which had significant impact on the propagation path of hot tearing. Introducing inclusions defect into stress analysis and comprehensively considering the induction and enhancement of inclusions on hot tearing can better improves the prediction accuracy of hot tearing, which has engineering guiding significance for casting process optimization and product quality control.