The COVID-19 epidemic is a newly emerging infectious disease. This study was conducted to design an appropriate psychometric questionnaire of cultural and social characteristics to evaluate beliefs and preventive behaviors toward COVID-19 among the Iranian's population according to change behavior theory as health belief model (HBM). The study population included all those who had access to social networks and answered the questionnaire voluntarily. The sample size in this study was 350 people. In this cross-sectional study, a questionnaire was designed using scientific sources and based on the health belief model, and its face and content validity was determined by Content Validity Ratio (CVR), and reliability was determined by the internal consistency; Test-retest was applied to examine the internal consistency of the questionnaire. Data were analyzed using SPSS software version 19. Cronbach's alpha and Intra-class Correlation Coefficient (ICC) were used for the assessment of the reliability of data. Initially, the questionnaire was designed based on the literature reviews and expert's opinion in the field of health education with 79 items. After that, 2 of them were deleted and corrected qualitatively by performing the face and content validity of some items. Therefore, finally, a questionnaire with 77 questions was approved. Based on the constructs of the health belief model, the domains of the questionnaire included perceived sensitivity, severity, benefits barrier, self-efficacy, knowledge and behavior.The content validity of the questionnaire was confirmed. The Cronbach's alpha and ICC for each domain were greater than 0.7. The Questionnaire of beliefs and preventive behaviors toward COVID-19 based on HBM is a valid and reliable instrument in the Iranian population that could be used in related research.