Via the phase diagram of diesel-rice bran oil biodiesel-ethanol blends at different purities of ethanol and different temperatures, the stability of the mix fuel system was studied. Fuel properties (such as density, heat of combustion, cetane number, flash point) of the selected blends and their emissions performance in a diesel engine were examined and compared to those of base diesel. With decrease of temperature, the solubility of diesel-rice bran oil biodiesel-ethanol blends system was decreased. The moisture content of ethanol had a great influence on mixture solubility. With increase of moisture content, the solubility of system was decreased. The fuel properties of blend were similar to those of base diesel. With the ethanol content of blends increasing，the power was decreased and BSFC was increased. The CO, HC and NOx emissions were increased when the ethanol content of blends was increased. The results show that the fuel properties, combustion properties and emissions of diesohol can be improved by adding rice bran oil biodiesel.