In this study, Pistachia Palestine oil was tested to determine its thermo physical properties and combustion performance. The ultimate analysis of this oil was conducted using a high pressure gas chromatography (model 2010). Moreover, the Pistachia Palestine oil was blended with diesel fuel at a ratio of 5, 10, and 15 (v/v%) and the fuel blends were tested in the Hilton combustion laboratory unit C 491 according to standard methods. Based on the fatty acid analyses, the elemental composition of the Pistachia Palestine was found to consist (wt%) of 76.4 carbon, 12.3 hydrogen, and 11.3 oxygen. Accordingly, the average chemical formula is C-17.44 H33.4O1.94. Compared with diesel fuel, Pistachia Palestine oil has a higher molecular weight, viscosity, density, pour point, and cloud point; whereas it has a lower energy content and stoichiometric air-fuel ratio. In addition, it was found that the stack temperature and the thermal efficiency of the combustion unit decrease when the fuel blends were being tested.