<p>The evolution of artificial intelligence has imposed more stringent demands on learners’ online learning. It is a pressing need to improve online learning outcome and, in turn, enhance the quality of online learning. This research aimed to explore the factors influencing learners’ online learning outcome, approaching the issue from the perspective of internal and external causes to examine the applicability of the Dialectical Principle of Internal and External Causes in distance education. A total of 234 Chinese pre-service teachers participated in the study. Analysis was conducted using a Structural Equation Model (SEM) constructed with the aid of SPSS and SmartPLS. The findings revealed that performance expectancy, self-regulated effort, and constructive interaction significantly enhanced learners’ online learning outcome. Whereas computer skills, teacher support, and school support did not exert a significant influence on such outcome. Additionally, internal factors were found to moderate the relationship between external factors and learners’ online learning outcome, thus validating the Dialectical Principle of Internal and External Causes in the context of distance education. These findings offer valuable insights for policymakers, school administrators, and teachers in the implementation of online learning.</p>