Abstract: The test and control systems of a high pressure common rail diesel engine were built based on a second generation of high pressure common rail fuel system of BOSCH. The influence of common rail system’s control parameters (such as starting fuel quantity, main injection advance angle) on starting characteristics was researched through experiments, and the varying tendencies of start time and HC emission were summarized. Test results show that: with the increase of the starting fuel quantity, the start time firstly decreases and then increases while HC emission increases all the time; There is an optimum value for the main injection advance angle, which makes start time shortest and HC emission lowest. If the main injection advance angle changes against that value, starting performance will be lower with longer start time and high HC emission.