CO conversion technique matched to coal gasification

This invention discloses a process for converting CO in pulverized coal gasification. The process comprises: introducing crude synthesis gas from pulverized coal gasification into a gas-liquid separator, mixing the gas from separator top with outside middle-pressure overheated steam, middle-pressure steam and a small amount of condensate from steam stripping, introducing into a pre-conversion furnace, controlling the temperature increase, introducing the converted gas into 1# conversion furnace, performing in-depth CO conversion, introducing high-temperature shift gas into a middle-pressure waste boiler to generate4.0 MPa steam with the condensate produced in the process, introducing all middle-pressure steam into fresh converted gas for recycling, quenching with the condensate for humidification, converting in 2# conversion furnace, cooling he converted gas by a water preheater, introducing into 3# conversion furnace, recovering waste heat until the output gas is less than or equal to 40 deg.C, and introducing into the following procedures. The CO concentration is decreased from 60-65 mol. % to less than or equal to 0.4 mol. %. The pre-conversion furnace can prevent catalyst poisoning. The pressure decrease of the conversion system is reduced, thus can ensure the pressure at the inlet of the synthesis gas compressor.