The invention discloses a photocatalytic type air purification device which comprises a spiral channel with an air inlet and an air outlet, wherein a plurality of catalytic units are arranged in the spiral channel; the catalytic unit comprises a catalyst carrier with a pore structure and a g-C3N4 optical catalyst attached to the catalyst carrier; the periphery of the catalyst carrier is hermetically connected with the inner wall of the spiral channel; the side wall of the spiral channel is made of light transmission materials; a visible light source irradiating the g-C3N4 optical catalyst is arranged in the spiral channel. The invention further provides a photocatalytic type air purification method. According to the photocatalytic type air purification device, the spiral channel structure is adopted for guiding air stream, so that the utilization rate of a space in the device is greatly increased, the path and the time for passing through the catalyst by air are prolonged, the area of contact between the air and the catalyst when the air passes through the catalyst is enlarged, the photocatalytic efficiency is improved, and the overall size of the device is reduced; the device is suitable for being used in various occasions.