It is well known that parents play an important role in the family, particularly the mental health literacy of parents is essential for the growth and development of children. As the parents of children with special needs, they are facing more difficulties and psychological pressure, resulted in more mental health problems. The current study examined the effect of social support on mental health literacy, and its underlying mechanisms regarding the mediating role of coping styles and moderating role of social comparison. Using a cross-sectional design, 165 parents of children with special needs (22-67 years old, M=37.72, SD=8.78) participated in the study. The general information questionnaire, Mental Health Literacy Scale (MHLS), Social Support Rating Scale, Simplified Coping Style Questionnaire, and Social Comparison Orientation Scale were used. We found that objective support positively predicted the mental health literacy, positive coping style played a mediating role between objective support and mental health literacy. In addition, the relationship between objective support and positive coping styles was moderated by social comparisons; for lower levels of opinion social comparison, the effect of objective support on positive coping styles was significantly stronger. We revealed the underlying mechanisms between social support and mental health literacy. The present study has profound implications for mental health literacy services for parents who have children with special needs.