The invention discloses a coal water slurry blended fuel engine oil composition. Polyinternalolefins and castor-bsae dioctyl sebacate used as base oil are matched with multiple composite additives to obtain the composition. The composite additives comprise an antiwear additive, an antioxidant preservative, an antifoam agent, a demulsifying compound, a viscosity index improver, a metal passivator, a detergent agent, a dispersing agent, an antioxidant, an oily agent, a friction improver, a reinforcing agent and a rust inhibitor. The engine oil composition has excellent cleaning and dispersion effects, prevents the piston ring from sticking, and keeps the engine clean. Due to excellent viscosity-temperature characteristic, excellent alkali number retentivity, acid neutralizing capacity and demulsifying capacity, the engine oil composition can inhibit the black oil sludge from generation, so that the engine is cleaner. Due to favorable high-temperature oxidation stability, high shear stability, favorable rubber compatibility, favorable cold-starting property and excellent fuel economical efficiency, the engine oil composition can not corrode or tarnish the moving parts, ensures the oil product to maintain sufficient oil film strength, has better extreme-pressure abrasion resistance, and lowers the abrasion and engine oil consumption.