A liquid control valve includes a base, a liquid stopper, an adjusting rod, and a linkage. The base includes a first chamber and a second chamber intercommunicating with each other. The base further includes an inner face having an upper stop portion. The liquid stopper includes a valve body movably received in the first chamber and a seal for abutting against the upper stop portion. The adjusting rod includes a fixing arm and an adjusting arm, which are connected to each other by a conical hole and a cone. An end of the fixing arm is pivotably connected to a first pivotal portion of the base. The linkage includes a driving arm and a connecting arm which are pivotably connected. An end of the driving arm is pivotably connected to a second pivotal portion of the base. An end of the connecting arm is pivotably connected to the fixing arm.