Increased population growth and economic growth, impact on the use of fossil fuels also increases, while the production of petroleum drop. To overcome this, a new breakthrough is needed replacing fossil fuels. Vegetable oil is in great demand for replacement fossil fuels because they can be updated and environmentally friendly. Vegetable oil has deficiency that is very high viscosity. To improve the oil characteristics vegetable is one way that can be done is to mix two type of vegetable oil in the form of biodiesel. Castor oil and corn oil including oil vegetable that has the potential to be biodiesel because it is composed of triglycerides. This study aims to determine the effect of mixed composition variation to the characteristics of biodiesel and to obtain mixtures according to SNI and ASTM . In this study the method used is the method of transesterification with using 15% methanol and 1% KOH compared to oil volume. Mixing of distance biodiesel and corn biodiesel using 60 minute reaction time and 60ºC reaction temperature with mixed composition variations between the distance biodiesel and corn biodiesel. After the sample of biodiesel mixture is followed by the test characteristics include density, viscosity, flash point , and calorific value. The results of the mixture of distance biodiesel and corn biodiesel tend to decrease values on the graph of testing of such biodiesel characteristics which include density, viscosity , flash point along with the increase of corn biodiesel composition in each variation the mix. In the assessment of biodiesel characteristics obtained two samples of mixed variation biodiesel whose characteristics meet the SNI and ASTM standards which are in composition 50% biodiesel distance and 50% biodiesel corn with viscosity value 4,9 cSt, density 887,094 kg / m³, flast point 192,1 ºC, calorific value 9131,55 cal / g and 10% biodiesel distance and 90% corn biodiesel with viscosity 4,9 cSt, density 860,569 kg / m³, flash point 171,1 ºC, value calories 9454,76 Cal /g.