Based on the contrast analysis of the physicochemical property of jet fuel and automotive diesel fuel， an experimental study on the external and load characteristics of jet fuel and diesel respectively was carried out on an electronically controlled high pressure common rail military diesel engine. Results show that compared with diesel operation， the dynamic performance of high pressure common rail diesel engine fueled with jet fuel is not obviously different. Under external characteristic conditions， the power and torque decrease by an average of 0.89%， and the brake specific fuel consumption decreases by 0.62%， the CO and NOx emissions decrease by 6.8% and 3.8% respectively and HC emission increases by 40.5%， with an average of 15.6%. Under load characteristic conditions， the brake specific fuel consumption decreases by 1.56%、 2.54% and 2.24% respectively （corresponding engine speed is 1 000、1 400 and 1 900 r/min respectively ）.