Issues with joint attention, especially avoiding eye contact with others, are considered one of the core defects found in the early stages of children with autism spectrum disorder (ASD). This study is the first to use pupil reflection technology, which can be used to present an image of the participants within the virtual character's eyes on the screen, thereby arousing their interest and promoting eye contact with the character during the interaction. The study evaluated the efficacy of pupil reflection as an internal cue to improve a participant's joint attention. A total of 63 children with ASD were asked to participate in the study. The stimuli materials were combined with internal cues and external cues. We found that, first, both the internal and external cues attracted the attention of the ASD participants and can play a prompting role in the intervention training. Second, the internal cues appeared to successfully simulate the real world in that the ASD participants paid more attention to the eyes. It can be used to improve eye contact with others. Third, there was no obvious interaction between the internal and external cues. This demonstrated that pupil reflection had a positive impact on the visual processing and joint attention of children with ASD.