Abstract: Bench tests were conducted for evaluating the wear characteristics of diesel engine fueled with biodiesel and No. 0 petro-diesel, respectively. The wear and morphologies of the engine were analyzed before and after the bench test. The results indicate that the wear extent of moving parts of the engines such as cylinder liner, piston, piston ring, connecting rod, connecting rod bearing, camshaft and fuel injection pump was all in normal range for the two diesels, but the wear of biodiesel engine is slightly less than that of petro-diesel engine. SEM analysis of the cylinder liner and piston ring also shows that the anti-wear performance of biodiesel is better than that of petro-diesel because of higher viscosity and better lubricity of biodiesel which more easily form a film on the cylinder wall.