Background: In research works, not paying attention to fathers' parenting and its effect on couples' relationships through indirect intervention with the leverage of helping children can be important, and satisfactory results can be achieved with this method. Purpose: The purpose of this research is to investigate the effectiveness of the intervention focused on increasing the father's activity in the co-parenting process and its effect on the intimacy and commitment of spouses and the father-child relationship. Methodology: The statistical population of this research included all the families with children in the fifth or sixth grade of elementary school in Bushehr city in the academic year of 1402, 32 families (32 men, 32 women and 32 children) were selected using the available method, then 16 families (16 men, 16 women, 16 children) were assigned to the experimental group and 16 families (16 men, 16 women, 16 children) were assigned to the control group. The research design was pre-test and post-test with control group. In order to analyze the data in this research, after extracting the results and descriptive analysis of the data and calculating the mean and standard deviation, one-way covariance analysis, multivariate variance and Yeoman-Whitney test were used. Findings: The results of the analysis of covariance showed that the significance level for the research variables was 0.001 fathers' marital intimacy, 0.001 fathers' marital commitment, 0.003 mothers' marital commitment, father-child relationship quality in fathers 0.18 and parent-child relationship quality. In children, it is 0.001, and the results of the Yeoman-Whitney test showed that the significance level for the variable of mothers' marital intimacy is 0.13. Conclusion: The results of this research show that the intervention focused on increasing the father's activity in parenting increases the quality of the relationship between spouses in terms of intimacy and commitment, and also increases the q