<p>The emergence of online course platforms (OCPs) provides a convenient channel for individuals to acquire knowledge, and also attracts learners to pay for knowledge. For these platforms, how to attract new learners as well as improve learner’s retention is an important issue. The purpose of this study is to analyze the mechanism by which learners’ satisfaction with the platform and learning behaviors affect their intention to knowledge cross-buying. In addition, we examine the moderating effect of knowledge product characteristics. To address these issues, we estimate the influence of learners’ satisfaction and learning behavior on knowledge cross-buying intention based on the probit regression method. The authors collected data from two online medical course platforms operated by a Chinese company. The dataset includes course information, learner’s behavior and login data of 3143 learners from January 2014 to December 2019. Knowledge cross-buying behavior occurs between this new platform and another existing platform. The results reveal that learners’ satisfaction and behavior with conviction positively impact knowledge cross-buying intention. Conversely, behavior without conviction does not have a significant impact, which may be attributed to path dependence. Furthermore, the effects of behavior with conviction are amplified when the courses are more difficult, while the effects of learners’ satisfaction are comparatively weaker. By examining the influence of OCPs learners’ learning environment and their learning behavior on the intention to pay for knowledge, as well as the moderating effect of knowledge product characteristics, this study explains the mechanism behind learners' payment for knowledge.</p>