The effect of filling speed, tracking range of liquid level, nozzle diameter and the shape of nozzle ondripping and foaming during filling process was studied using orthogonal test method. The best operation parameters of the liquid filling system were determined. The result showed that the main influencing factors on drip phenomenon are speed in low speed period and shape of the nozzle; the main influencing factors on foaming phenomenon is nozzle diameter and tracking range of liquid level. The purpose was to provide gaidance for piston liquid filling system design and parameters selection.