Disruptive technological innovation is regarded as a key driving force for modern industrial transformation and upgrading, yet its innovation spillover effects within the industrial chain and the underlying mechanisms remain insufficiently explored. Based on invention patent data and industrial chain linkage information of Chinese listed firms, the effects of disruptive technological innovation on the innovation quality of upstream and downstream firms were systematically examined from an industrial chain perspective, and the associated mechanisms and heterogeneity were further analyzed. The results indicate that disruptive technological innovation conducted by listed firms generates significant innovation spillover effects along the industrial chain. However, these spillover effects exhibit pronounced asymmetry due to differences in industrial chain positions and the diffusion characteristics of disruptive technologies. Specifically, a significant forward spillover effect is observed, whereas the backward spillover effect is not significant. Mechanism analysis shows that the spillover effects are mainly transmitted through technological trajectory reconstruction and increased technological integration depth, which contribute to the improvement of downstream firms' innovation quality. Heterogeneity analysis further reveals that the spillover effects are more pronounced among downstream firms with stronger absorptive capacity and larger firm size, while a weaker innovation response is observed in downstream firms with higher ownership concentration. These findings provide new empirical evidence for understanding the innovation spillover effects of disruptive technological innovation within the industrial chain and their transmission mechanisms.