Engine experiments were conducted on a 4102QB DI diesel engine to study the effects of the mixed fuels on engine performance and emission characteristics. The fuels are pure 0# commercial diesel fuel and its blends containing different proportions of methanol. Compared with pure diesel, blended fuels lower the engine power output a little. The emissions of smoke and CO are reduced with the increase of methanol percentage, while the emissions of NOx and HC increase under the same engine operating parameters and conditions.