The paper first introduces the background and the mechanism of secondary pollution from desulfurization in cement plant. Then, take plant A as an example, using MGGH (media gas-gas heater) to control “white smoke”. MGGH uses heat medium water to heat transfer between the original flue gas and the clean flue gas, without additional heat source, and has obvious economic benefits, which is the inevitable development direction of desulfurization reform of cement kiln system in the future.