An apparatus for detecting the sealability of a lithium ion cell comprises a container which is filled with a detecting liquid, a clamp and a high-pressure-gas joint member. The clamp can carry a lithium ion cell to be detected and put it into said container. One end of the high-pressure-gas joint member is connected to an injecting hole of the lithium ion cell to be detected and the other end is connected to a high-pressure gas supply. The detecting apparatus also comprises an elevator which can move the lithium ion cell into and out the detecting liquid within the container.