Abstract: A thermal power plant exhaust purification device, the device including a cooling substance flow channel and an exhaust flow channel; the device also includes a spacing member for spacing and exchanging heat between the cooling substance flow channel and the exhaust flow channel, the spacing member having an exhaust contact surface for collecting dust and/or mist contained in the exhaust; the cooling substance flows in the cooling substance flow channel, such that the condensate precipitated from hot exhaust uniformly adheres on the exhaust contact surface, thus forming a uniform and stable water film; on one hand, formation of the concentrated H2SO4 on a dust collecting plate is prevented, and a liquid film flows downwards under gravity, thereby cleaning the H2SO4 adhered on the dust collecting plate timely; on the other hand, the water film is very effective in intercepting droplets and capturing the dust.