Nowadays, internet technology provides an opportunity for banks and financial institutions to take advantages in dynamic and competitive turbulent environment in their favor. In addition, considering the importance and status of internet banking and growing trend of it in the country in recent years, now banks and financial institutions have found that maintaining status and effective development without the benefit of scientific and practical strategies in information and communication management is not possible. However, the use of these services by bank customers would be met with resistance in some cases because of various reasons. In Refah Bank, despite practices and advances in the field of internet banking and conducting massive publicity, still many users of this service are not significant. Thus, the present study examined factors affecting the acceptance of online banking by consumer and tried to focus on the risk factor that appears to have a greater impact on the acceptance. This study, in term of objective is applied, and research method is descriptive from type of survey. Statistical population includes customers of Refah Bank in Qazvin Province of Iran that use the internet banking. Number of them to September 2013 is 15,041 people. Questionnaire was used to collect data and structural equation modeling and Lisrel software were used for data analysis. Results show that all the factors influencing the acceptance of online banking such as perceived usefulness, perceived ease of use, perceived enjoyment and quality of internet connection affect intention to use it. Also, regarding to the dimensions of perceptual risk, results indicate that social risks and security risks have a negative impact on the use of online banking services, but a negative impact of executive risk, time and financial is not proved.