Teachers can handle learning situations during activities in peer-to-peer classes, and assess student achievements associated with teaching goals in the affective domain. In distance learning, teachers cannot directly observe student states and assess achievement concurrently. Many distance education studies adopted frequency of interaction as the basis of student participation when assessing the student achievements in class. However, the number of times a student interacts is not equal to discussion quality. Although synchronous discussions during class can help teachers assess learning states, these discussions are no suited to all courses. If a teacher can supervise student images from computer’s webcam and observe student status, the teacher can assess achievement accurately. Image processing technology can be applied in an assessment system in distance learning, student states can be observed and these observational results can be combined with behavior detection to help teachers assess student achievement in terms of teaching goals in the affective domain. This study had analyzed the theory and method of assessing affective domain teaching goals. The assessment system had been implemented and simulated using image processing technology and records to analyze student achievement of attending and responding stages with a class period, via fuzzy logic and a fuzzy integral. Simulation results indicate that this assessment system can accurately assess student achievement in terms of attending and responding stages of affective domain teaching goals