In the present time, energy has become very important in supporting human activities. One of the energy sources needed is energy from the fuel. So far the types of fuel used is taken from fossil fuels. The current high demand for energy from fossil fuel production continues to increase, while fossil fuels are very limited. There are several objectives in this research, which are to know the fatty acid content found in the castor oil (minyak jarak) and calophyllum oil (minyak nyamplung), to know the nature and characteristics of mixture between castor oil and calophyllum oil, and to know the influence of the variation of heating time to the nature of oil mixture. In this research, there is a mixture between castor oil and calophyllum oil. The mixing of both materials was carried out at 120°C for 30 minutes with a mixture of 100%-0%, 90%-10%, 80%-20%, 70%-30%, 60%-40%, 50%-50%, 40%-60%, 30%-70%, 20%-80%, 10%-90% and 0%-100%. In the variation of heating time, there are 3 variations of heating time which are 30 minutes, 60 minutes, and 90 minutes. The test on the physical and chemical properties obtained results: The density value of 100% castor oil is higher than in 100% Calophyllum oil. In addition, high density value in the mixture of castor oil and calophyllum oil is found in oil mixture whose composition is dominated by castor oil. The viscosity value of the castor oil is higher than the viscosity value of calophyllum oil. In addition, the viscosity fluid in the mixture of castor oil and calophyllum oil is found in the oil mixture which is dominated by castor oil. The calorific value of the castor oil is lower than that of calophyllum oil. In addition, the high calorific value of the oil mixture of castor oil and calophyllum oil is found in oil mixture whose composition is dominated by calophyllum oil. Flash point oil value of castor oil is higher than calophyllum oil. In addition, high flash point value is found in oil mixture whose composition is dominated by castor oil rather than the one which is dominated by calophyllum oil. Fatty acids that dominate the castor oil is linoleic acid with 41.59% and calophyllum oil is dominated by oleic acid with 36.59%.