The invention discloses a coal powder gasification device and process for producing a coal gas with a high heating value and low carbon residues. The coal powder gasification device comprises a U-shaped coal gas generation furnace and a coal gas separation device, wherein the U-shaped coal gas generation furnace consists of a high temperature section and a low temperature section which are arranged in a U-shaped manner; the high temperature section and the low temperature section share one ash hopper; the high temperature section is a downstream air flow bed; the low temperature section is anupstream air flow bed; the inlet of the coal gas separation device is communicated with the outlet of the low temperature section; the solid outlet of the coal gas separation device is communicated with the inlet of the high temperature section; the gas outlet of the coal gas separation device is communicated with a coal gas waste heat utilization and purification system. By adopting the coal powder gasification device, the utilization rate of coal can be greatly increased.