The invention discloses a coal-prepared coal gas energy-conservation and emission-reduction method and device, and the purposes of energy saving and emission reduction are achieved mainly through a two-section type coal gas cooler and a waste heat boiler. Crude coal gas generated in a coal gasifier is cooled by the waste heat boiler, and at the same time, steam is by-produced by the waste heat boiler; coal gas discharged out of the waste heat boiler is dedusted, then enters an upper-section shell pass of the two-section type coal gas cooler and is cooled again; at the same time, softened water is initially pre-heated through a waste heat boiler ash hopper, a cyclone dust collector ash hopper and a cloth bag dust collector ash hopper in turn and is finally pre-heated to a certain temperature through an upper section of the two-section type coal gas cooler; and coal gas going out of the upper-section shell pass of the two-section type coal gas cooler enters a lower section of the two-section type coal gas cooler and is finally cooled by circulating cooling water. The method and the device can greatly reduce production of wastewater containing phenol and ammonia, moreover, can realize use of low-grade coal gas heat, improve the output of the by-product steam, and increase economic benefits of factories while achieving energy conservation and emissions reduction.