Abstract: This paper studies the feasibility of testing liquid leak rate with the vacuum method. Based on the theoretical analysis of the saturated vaporization pressure, the constant-volume pressure increment is obtained. Then by using a micro infusing system and a vacuum method, i.e. the static pressure rise method, the liquid leak testing is carried out for C2H4(OH)2 and (C2F5)3N. The results show that there is a linear relationship between the leaking liquid volume V and the pressure increment ΔP, as in agreement with the theoretical calculation, which shows the feasibility of the vacuum method for testing liquid leak rate. The static pressure rise method with a micro infusing system for calibration is proposed and the calculation formula is obtained. It is shown that this method is effective for testing liquid leak rate, as a tool in the liquid flowing test study.