Background: The disability to recognize emotional and mental states in others’ facial expressions is acknowledged as one of the major developmental-behavioral problems in children with autism. Therefore, it is necessary to study the effect of facial emotion recognition training on the interaction skills of children with autism. Objectives: The aim of this study was to investigate the effect of emotional facial recognition on the mother-child relationship in children with autism. Methods: The present clinical trial was conducted based on a pre-test post-test design. Children aged 6-12 years with high- or moderate-functioning autism were assigned to two groups using the random block sampling method. Children in the intervention group were trained in 10 45-min sessions each week for 10 weeks using 40 images related to four situations of happiness, sadness, anger, and fear. The mother-child relationship questionnaire was completed one day before and one day after the intervention in both groups by the research assistant. Data were analyzed with SPSS software version 22. Results: Emotional state training improved the mother-child relationship in the intervention group. There was also a statistically significant difference between the total scores of the mother-child relationship in the intervention group and the control group (p