The invention provides a process for preparing low-hydrogen CO gas, which mainly comprises the steps of (1) selecting anhydrous low-hydrogen coke, or firstly, dehydrating low-hydrogen coke, preparing crude gas with anhydrous carbon dioxide and oxygen in a gas-making furnace, recovering heat of the crude gas, and removing tar, dust impurities and strong acid ingredients; (2) carrying out process gas maintenance or heating to a temperature of 30 to 80 DEG C to enter a hydrolysis desulfidation tower to remove most of sulfides, carrying out mixed loading or laminated filling of an organic sulfur hydrolysis agent and a H2S oxidative desulfurization agent; (3) separating CO2 by process gas and simultaneously removing most of residual sulfides to prepare the CO gas, wherein the obtained sulfur-containing CO2-rich gas is returned into the gas-making furnace for recycling; the hydrolysis desulfidation tower is provided with vertical heating sleeves, and hydrolytic agent and desulfurizing agent bed layers are formed between the sleeves; the hydrolysis desulfidation tower melts and gasifies trapped elemental sulfur to blow out the same in the process of carrying out thermal regeneration at a temperature of 200 to 300 DEG C, and then the product is collected by a regeneration condenser to obtain sulfur. The process is simple and reliable in desulfuration process, easy to control, high in elasticity of processing capacity, high in adaptation to content and fluctuation of H2S and COS, safe, environment-friendly and low in operation cost.