With the discharge of urban sewage sludge is rising, and the demand for resource utilization of high moisture sewage sludge is crucial. Hydrothermal carbonization of low-rank coal and sewage sludge can utilize the sulfur and nitrogen elements in raw materials effectively andprepare sulfur and nitrogen doped hydrochar. Hydrochar had relatively less abundant pores, and activation by activator can enrich its porestructure and prepare sulfur nitrogen co-doped porous carbon. In this paper, relatively mild K CO was chosen as an activator for porous carbon preparation from co-hydrochars of sub-bituminous coal and sewage sludge, and the adsorption performance of porous carbon onCO and SOwas also studied. The results showed that compared with those of the original hydrochars, the sulfur and nitrogen contents reduced after the activation modification by KCO, and the specific surface area of the porous carbon was increased from 23.92 m / g to331.77 m / g, and the pore volume was increased from 0.07 cm / g to 0.23 cm / g. The prepared porous carbon had certain adsorptioneffect on CO and SO. For the hydrochar obtained from co-hydrothermal carbonizaiton at the condition that the mass ratio of sub-bituminous coal to sewage sludge was 7 ∶ 3, and the hydrothermal carbonization temperature was 160 ℃ , activated by KCOat 700 ℃ , the porous carbon has a CO adsorption capacity of 1.56 mmol/ g at 25 ℃ ; when the mass ratio of sub-bituminous coal to sewage sludge was 1 ∶ 1and the hydrothermal carbonization temperature was 160 ℃ , the activated hydrochar prepared had an adsorption capacity of 52.2 mg/ gfor SO at an adsorption temperature of 120 ℃ . The adsorption amount decreased with the increase of the hydrothermal carbonization temperature, and the adsorption performance of the porous carbon from co-hydrochar was better than that from the separate hydrochar for COand SO. The results may provide a theoretical basis for the clean and efficient utilization of low-rank coal and sewage sludge, as well asfor the preparation of low-cost and efficient CO and SO adsorbent.