Knowledge sharing effectively promotes upgrading the industrial chain towards high-end levels through industrial technology innovation strategic alliances (ITISAs). Based on the characteristics of ITISAs, this paper applies structural equation modeling (SEM) to data obtained from a questionnaire to analyze the influencing factors of knowledge sharing in ITISAs. The results show that: The willingness to share knowledge and tacit knowledge characteristics significantly positively and negatively impact the knowledge-sharing recognition stage, respectively. Second, the subject heterogeneity has a significant negative impact, and the knowledge-sharing environment and information technology significantly positively impact the knowledge-sharing implementation stage. Third, the knowledge absorptive capacity has a significant positive impact on the knowledge-sharing integration stage, and the knowledge-sharing process has a significant positive effect on the knowledge-sharing effect. This study contributes information that may guide ITISAs to improve their technological innovation capability by considering the factors that influence each of the three stages of knowledge sharing.