The diesel engines are widely used in public transport vehicles. Its emissions of smoke, NOX, HC and PM cause air pollution, and affect human health seriously. In this study, we used Fischer-Tropsch diesel fuels and mixed methanol and isopropyl alcohol with the Fischer-Tropsch diesel fuels and filled into vehicular diesel engine tank. The experiment results show that adding methanol and isopropanol in Fischer-Tropsch diesel fuels can help to improve the problem of diesel engine exhaust emissions. In particular, it effectively reduces the engine exhaust smoke and HC concentration.