Nowadays, biomass fuels become a subject which is extensively concerned from the view points of the aggravation of the greenhouse effect, acid rain, other environmental problems and the depletion of oil resources. From the point of this view, this experiment has been carried out to examine the influence of combustion characteristics and exhaust emissions for small diesel engine by using six types of fuel, which consist of different pure ethanol and butanol volume percentages (10vol.%, 20vol.%), with 3 vol.% surfactant at 20vol.% and 10vol.% aqueous alcohol (ethanol: 65 vol.% or butanol:65vol%, water: 35vol.%) . The combustion behaviors, such as burning pressures, heat release rates and emissions (NOx, Smoke, HC) and fuel consumption are observed. The main conclusions are as follows: 1) NOx and Smoke can be reduced simultaneously by using diesel fuel-alcohol mixed fuel and water emulsion fuel. 2) HC emission decreased by using diesel - butanol mixed water emulsion fuel. 3) The maximum heat release rate is increased by using diesel - alcohol mixed fuel and water emulsion fuel. 4) The heat release stability of diesel - butanol mixed fuel and water emulsion fuel are higher than that of ethanol addition fuels.