A five-pole,six-shoe and twenty-four-tooth ferrofluid rotary sealing device was designed for the sealing problem of the high-speed centrifugal pump in the rapid cooling system of the waste incineration project.This device is suitable for incineration high-temperature flue gas environmental conditions and has a long service life.The pressure resistance formula with considering the temperature field and centrifugal force was theoretically deduced.It is concluded that the pressure resistance is the quadratic function of the linear velocity,and the linear function of the temperature.The Ansys was used to calculate the magnetic field distribution of the structure under the gaps of 0.4,0.5,0.6 and 0.7 mm.It is found that the pressure resistance of the sealing structure gradually increases with the decrease of the sealing gap,and due to the existence of magnetic leakage,the degree of increase of the pressure resistance is not linear.The distribution of magnetic field lines shows that the magnetic leakage is a little larger at the first and sixth pole shoes ,the second and fifth pole shoes.In the sealing experiment,it is concluded that when the maximum gap is 0.7 mm,the single-stage sealing pressure capacity reaches at 51.7 kPa.