Abstract: In order to study the influence of methanol distillation residue （MDR） on the properties of coal water slurry （CWS）. Using Shenmu coal from Shaanxi Province as raw material, MDR was employed to partially or completely replace water in slurry preparation. Through comprehensive analyses including apparent viscosity, zeta potential, surface tension, contact angle, thermogravimetric analysis （TG–DTG）, and BET specific surface area, the competitive mechanisms among electrostatic repulsion, van der Waals forces, and hydrogen bonding in slurry systems were systematically examined to elucidate the influence patterns of MDR on CWS formation and pyrolysis characteristics. Experimental results demonstrate that under constant shear rate conditions, slurry viscosity exhibited a characteristic trend of initial decrease followed by increase with incremental MDR addition. The optimal viscosity （808.7 mPa·s） was achieved at 9.25% MDR Regarding stability, the minimum water separation rate （5.24%） occurred at 7.40% MDR content, while dosage, beyond which excessive addition induced rapid viscosity elevation and deteriorated dispersion. overdosing altered interparticle interactions, resulting in increased water separation and stability degradation. Pyrolysis analysis revealed that MDR-derived low-molecular-weight alcohols generated reactive intermediates during initial pyrolysis stages. Enhanced specific surface area and porosity of third-stage pyrolysis coke were observed with increased MDR addition, accelerating coal decomposition and elevating mass loss from 45.6% to 51.4%, thereby optimizing pyrolysis efficiency. The findings indicate that moderate MDR incorporation improves CWS rheology, stability, and pyrolysis performance, whereas excessive usage adversely increases viscosity and reduces stability. The co-processing of MDR in CWS gasifiers presents a novel approach for resource utilization of methanol distillation residue, offering potential benefits for cost reduction and efficiency enhancement in chemical enterprises. This research provides theoretical guidance and technical support for industrial implementation of MDR-CWS co-processing technology.