The present study was conducted to investigate the effectivness of acceptance and commitment therapy on the family function and satisfaction of the marital life of the couples with marital conflicts. The research method of the present study was quasi-experimental with pretest, posttest and control group design. The follow-up period was administered in two months. The statistical population of the present study included the couples with marital conflicts who referred to consultation and wellbeing centers in zone two of Mashhad in the spring and summer of 2021. 20 couples (40 people) were selected through purposive sampling method and randomly accommodated into experimental and control groups (10 couples in the experimental group and 10 in the control group). The experimental group received acceptance and commitment therapy (10 sessions) during ten weeks. The applied questionnaires in this study included marital life questionnaire (Barati and Sanaei, 1996), family function questionnaire (Epstein, Baldwin, Bishop, 1983) and marital life satisfaction (OLson, 1996). The data taken from the study were analyzed through mixed ANOVA and Bonferroni follow-up test via SPSS23 software. The results showed that acceptance and commitment therapy is effective on the family function (F=49.91; Eta=0.57; P<0001,) and marital life satisfaction (F=64.01; Eta=0.62; p<0001) of the couples with marital conflicts. According to the findings of the present study, acceptance and commitment therapy can be used as an efficient approach to improve family function and marital life satisfaction of the couples with marital conflicts through forming psychological felexiability and making mental acceptance.