Background Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder that being stigmatized by the frontline educators. However, research targeting on the preservice teachers is scarce. Guided by the common sense model, a psychoeducation training about ASD was developed to understand pre-service teachers' attitude and to address the myths with comprehensive information.Methods A total of 233 undergraduate students studying educational programs completed a pre-test questionnaire, psychoeducation training, and a post-test regarding ASD. Among them, 216 participants completed a one-month follow-up measure. The hypotheses were tested using bivariate correlations and repeated measure t-test.Results The results of the bivariate correlations between the perceived chronicity and consequence of the course of ASD were positively associated with stigma and preferred social distance. By using the paired-sample t-test, the results suggested that participation in psychoeducation training could help to increase pre-service teachers' knowledge and reduce their stigmatizing attitudes towards individuals with ASD. A shorter preferred social distance and more acceptance level were significantly associated with improved knowledge at the post-test. The results of improved knowledge and decreased stigma were also observed one month after the psychoeducation training.Conclusion Theoretically, the present study indicates that the common sense model contributed to a deeper understanding of the attribute of the negative attitudes towards people with ASD. Practically, the effectiveness of the psychoeducation training on improving knowledge might provide some insights for the future development of knowledge-based interventions that mitigating the stigma associated with ASD. The findings could also guide the design of the teacher-training programs on special education to better prepare the pre-service teachers on their teaching professions. All rights reserved.