The invention discloses a method and an apparatus for detecting the liquid permeability of a micro-porous grid sheet. Existing liquid permeability detection methods have the disadvantages of no general standard, low precision and difficulty in realization. The method comprises the following steps: a liquid to be detected is injected into a beaker, the feed amount of a feeding device is adjusted, and the feeding device and a high-speed digital microscopic system are placed in a shell; the pressure and the temperature in shell are kept constant; the opening and the closure of an electromagneticstop valve arranged at a syringe needle are controlled, the feeding device drives the tail part of a microsyringe to move, the microsyringe injects the liquid, and the liquid goes through a permeationtube and flows to a permeation plate; the high-speed digital microscopic system performs high-speed photography, and acquires the height and the permeation time of the liquid to be detected in the permeation tube; and the volume change amount of the liquid injected by the microsyringe is obtained, and the permeation coefficient is calculated. The method disclosed in the invention is characterizedby high-speed photography of the process of the liquid permeating the micro-porous grid sheet, and analyzing and calculating the permeation time, the permeation pressure, the permeation volume and other parameters.