The world has widely used continuous filter tanks. For processing water supply, "Continuous circulating sand filter tank" is an advanced technology, technology new technology, has been applied in Ho Chi Minh City, Khanh Hoa, Phu Yen... In Quang Nam, an experiment was conducted with the results of the research process also launched a product of continuous circulating sand filter tank with a capacity of 400m3/day and has been tested by the Company at Tam Hiep Thermal Power Plant, Nui Thanh district, Quang Nam province in 2011. However, some parameters such as The formula for calculating the area of the continuous filter tank has not been studied, so in the article This article deals with the calculation of continuous filter tank parameters.