Computers and the Internet are indispensable in modern life. Increasingly useful digital environments and technological developments have reshaped models of knowledge acquisition. Studies on the development of online learning have yielded valuable insights. In the design of online teaching systems that can replicate face-to-face teaching, user-friendly design is a key factor determining whether a system is immediately accepted by users. In this study, we designed an affective tutoring system (ATS) for curriculum teaching. Participants' learning processes were recorded during ATS teaching sessions. Negative emotions in the participants were recognized in real time and recorded in a learning state database. We determined the learning outcomes of students who were taught using the ATS or normal online learning. The experimental results indicated that the ATS is an effective tool and significantly improves learning outcomes.