Considering the importance of intention to receive COVID-19 vaccine among healthcare workers and its role in maintaining their health and inhibiting the epidemic spread of Covid-19, the present study was done to identify the changes in intention to receive COVID-19 vaccine rate in two different time points and it's determinants based on the dimensions of the health belief model among healthcare workers in Iran.Two cross-sectional surveys performed to investigate COVID-19 vaccination intent and associated factors based on the health belief model. The first conducted on 1244 participants from August 18 to 23, 2020, and the second on 1514 participants from February 5 to April 29, 2021, both using a questionnaire of intent to accept COVID-19 vaccination. The questionnaire distribution platform in both surveys was similarly, WhatsApp and Telegram social and working virtual groups of HCWs. Data were analyzed with SPSS-16 software for descriptive and analytical statistics.In the first survey, 58.4% (95% CI: 0.55-0.61%) of healthcare workers intended to receive the COVID-19 vaccine, the rate dropped to 45.7% (95% CI: 0.43-0.48%) in the second survey (P < 0.001). The regression analysis indicated six factors that were significantly associated with higher intention to receive COVID-19 vaccine: being a female (OR = 1.84, 95% CI (1.11-3.03)), history of Covid-19 infection (OR = 1.54, 95% CI (1.09-2.18), perceptions of Covid-19 disease (OR = 1.13, 95% CI (1.01-1.28)), perceived benefits of COVID-19 vaccine (OR = 1.34, 95% CI (1.22-1.47)), prosocial norms for COVID-19 vaccination (OR = 1.25, 95% CI (1.21-1.29)), and COVID-19 vaccine safety/cost concerns (OR = 1.25, 95% CI (1.17-1.33)).Present study showed an undesirable rate of intention to receive COVID-19 vaccine among healthcare workers, especially decreasing over the time, emphasize the need of interventions to promote healthcare workers' intention to receive the vaccine and reduce the spread of COVID-19 disease.