The COVID-19 pandemic has had a huge impact on people's health, and countries' infrastructures around the globe. Iran was one of the first countries that experienced the vast prevalence of the coronavirus outbreak. Iranian government applied various nonpharmaceutical interventions to eradicate the epidemic in different periods. To evaluate the effectiveness of applied policies, the number of cases and death before and after the interventions studied and the effective reproduction number of the infection was analyzed under various scenarios. The SEIR generic model was applied to capture the dynamic of the pandemic in Iran. It is assumed that changes in reproduction number are responses to interventions. Depending on how responsive people to the government interventions, the effectiveness of each intervention has been investigated. Based on the model results, the peak of the total number of infected individuals will occur around the end of May and the start of June 2021. It is revealed that the outbreak had been able to be smoothed if the government had continued the full lockdown and strict quarantine. The result will allow for the assessment of the effects of different government interventions in new outbreaks.