In view of the problem of a high magnetic fluid temperature during operation of a certain type of high-temperature magnetic fluid in a high temperature MHD dynamic seal structure, a structural optimization scheme has thus been proposed to add cooling water channels and insulation air holes to the original structure, so as to reduce the working temperature of the magnetic fluid in the high-temperature working environment, thus ensuring a working temperature within the required working range. Based on a comparison between the temperature, pressure, and velocity fields of the sealing device under two different heat source temperatures before and after structural optimization, a further analysis has been made of the heat dissipation characteristics of the sealing structure and the feasibility of optimization. The analysis results indicate that changes in temperature and structure have no significant impact on the pressure and velocity fields, while adding heat dissipation channels and insulation pores helps to effectively reduce the temperature of the overall structure. After optimization, with the heat source temperature reaching as high as 700℃ or 500℃, the maximum temperature in the MHD domain decreases by 173℃ and 95℃ respectively, thus significantly reducing the temperature of the magnetic fluid during operation. This structural optimization plan can reduce the temperature of the magnetic fluid to the normal working range, and improve its service life, thus providing certain reference value for the optimization of the magnetic fluid sealing structure.