Retaining learners has been an important issue for massive open online course (MOOC) platforms. Given the different, and even contradictory, conclusions in studies on the continuance intention of MOOC learners, this study selected 53 highly correlated empirical studies published from 2008 to 2022 and constructed a research model based on visual knowledge map analysis. Meta-analysis was applied to identify the key factors, and subgroup analysis was conducted to explore the moderating effect of mandatory participation and prior learning experience. The results show that attitude and satisfaction play the most significant role. Perceived usefulness, perceived ease of use, confirmation, social influence, perceived enjoyment, outcome expectation, self-efficacy and task-technology fit all play essential functions, while the direct impact of social presence requires further research. Prior learning experience and mandatory participation have moderating effects on perceived usefulness. MOOC developers should make more efforts and improvements in content quality, social quality and service quality.