Abstract Aim: To determine the efficacy of health beliefs model –based intervention in changing the belief related to substance use among university student in Mosul city-Iraq. Design: A randomized controlled trial. Methods: A probability (simple random sample) of (N=80) undergraduate student in different specialties would be selected. The study sample will be recruited from (4) colleges in the University of Mosul's Engineering, Sciences, Medicine and Education Colleges. The sample will be randomly assigned into experimental and control groups of (40) undergraduate student for each group. Such chosen is employed of pool of topics that have the criteria contain students who have using on (Smoking, Hookah, Drug abuse and Alcohol).For during from 25of October / 2019 till 1 of February/2021. Data is analyzed using the "Statistical Package for Social Science" (SPSS) software for Windows (V:26). Results: This finding indicated that before the intervention, mean scores for all concepts of HBM, add to Motivation, Control, and behaviors intensions of students they were almost equal. However, after the intervention were significantly different in the study group, while it was not significant in the control group. Conclusion:This study concluded that designing an HBM-based study could affect students' understanding and their behaviors in the field of substance abuse. Considering the positive correlation between construct of HBM, particularly in "perceived benefits and perceived severity" related to students’ beliefs. These beliefs implied a significant correlation with each other and with the attention to the prevention of addiction.