Production of fuel oil in Indonesia from year to year continues to decline. Calophyllum inophyllum biodiesel fuel is an alternative fuel that can be used in diesel engines. Gasoline is a fuel that can improve the characteristics of biodiesel. This research uses petrodiesel fuel, B30 (70% petrodiesel and 30% calophyllum inophyllum biodiesel), and B30 added with gasoline with a concentration of 10% vol/vol. The experiment was carried out with a direct injection single cylinder diesel engine connected to a generator that was used as a dynamometer and a gas analyzer was installed. Tests were carried out using lamp loads of 200, 400, 600, and 800 watts at a constant engine speed of 2000 rpm. The results of this research inform that the addition of gasoline to B30 fuel can reduce fuel consumption and increase thermal efficiency. The role of gasoline can also reduce CO, HC, and CO2 emissions. The addition of gasoline needs to be investigated further so that it can be applied to industry and transportation.