Abstract: The complexity of multi-hole orifices' geometric description results in the designing difficulty, fewer systematic design methods, and little research about the geometric parameters' influence on the multi-hole orifices' pressure loss coefficient and discharge coefficient. In this paper, we firstly investigate the effects of circular and rectangle arrangement with or without center hole, and obtain that the multi-hole orifices at the same geometric parameters perform well when the geometric arrangement is fixed as the circular arrangement with center hole. Then, we analyze the influence of the geometric parameters, i.e., the number of holes, the equivalent diameter ratio, and distribution density. It is shown from Matlab diagram that the equivalent diameter ratio has greater effect on the performance of multi-hole orifice than the number of holes and distribution density. Hence, it is feasible to adopt the equivalent diameter ratio as the dominant parameter affecting the performance of multi-hole orifice.