The utility model provides a sulphur dioxide fan. The sulphur dioxide fan comprises an enclosure, a fan spindle, an impeller rotor set, a dry gas mechanical seal assembly, a bearing box, an air inlet and an air outlet, wherein the enclosure and the bearing box are supported by an enclosure support, the impeller rotor set is fixed on one end of the fan spindle by adopting an impeller pair cap, the dry gas mechanical seal assembly is used for sealing the enclosure and the fan spindle, the air inlet is arranged in the axial direction of the impeller rotor set which is arranged on the fan spindle, the air outlet is arranged in the radial direction of the fan spindle, the bearing box is arranged on the fan spindle by virtue of a sliding bearing, and the bearing box and the two ends of the fan spindle are sealed by virtue of a high carbon ring. According to the sulphur dioxide fan disclosed by the utility model, the dry gas mechanical seal assembly and the high carbon ring are used for realizing sealing and assembling, and the problem that the fan has faults frequently can be solved, so that an acid making system can continuously and stably operate, and working efficiency is improved further.