Field tests were conducted to research the emission characteristics and environmental risks of polycyclic aromatic hydrocarbons (PAHs) during co-processing of coal liquefaction residue (CLR) in Texaco coal-water slurry gasifier. Comparing the differences between blank condition (without mixing CLR in the slurry) and test condition (15% CLR were mixed into the slurry), the changes of temperature, pressure and syngas composition in the gasifier were recorded, the toxicity equivalent concentration of 16 kinds of PAHs in all the solid, liquid and gas emissions were analyzed to evaluate the feasibility and environmental risks during the co-processing of CLR in Texaco coal-water slurry gasifier. Results showed that during the co-processing process, there had little impact on the pressure and syngas output of the gasifier, but made an increase of 5~11℃ of the temperature and promoted the formation of H₂ and CO; the concentration of PAHs in part of the gas emission and liquid emission increased a little, but the toxicity equivalent concentration was still far lower than the standard limitation, has low environmental risk; the concentration of PAHs in solid emission products increased significantly, but the total toxicity equivalent concentration was also low, the environmental risk was in the acceptable range.