Chromic acid recovery system consists of two support systems: the chromate recycling exhaust gas recycling of water recycling and chrome fog. Chromic acid recovery principle of electrolytic heating evaporation with the chrome fog recycling condensation method, the recovery tank after chrome plating chromium in the water and exhaust gas containing chromic acid mist particles, first by electrolysis syrup impurities, re-use heating evaporation the chrome recovery tank syrup and water, chromic acid particles in the exhaust gas through the multi-layer plastic stencil, due to chromic acid mist the chromic acid fine particles collide with each other through the twists and turns away condensation into droplets and condensed into stencil barrier liquid (due to chromium droplet freezing point higher), chromic acid liquid along the stencil inflows under the guide groove, and then to the main plating bath, the purified gas smoothly through the stencil by FRP fan emissions space. As long purifying effect, at the top of a washing liquid inlet nozzle then every other week to open the spray valve, cleaning multi-layer plastic stencil to stencil a long time without clogging, cleaning the waste water and then discharged to the chromium recovery tank