The invention relates to a gravity sensor based grain moisture rapid detection device. The gravity sensor based grain moisture rapid detection device controls a stepping transmission mechanism to translocate through a singlechip, three stations of a feeding station, a detection station and a material removal station are circularly switched, the feeding station, the detection station and the material removal station are arranged in a rack, a detection mechanism is provided with a heating mechanism and a support frame, a gravity sensor is installed at the lower part of the support frame, the material removal station is provided with a cam track and a material removal plate; when running to the material removal station, a moving glass cover mechanism and a moving material tray mechanism ascends along the cam track, the material removal plate scrapes the material on a moving material tray, when the moving glass cover mechanism and the moving material tray mechanism run to the detection station, the heating mechanism is located right above a glass feeding cylinder, a third idler wheel just corresponds to the support frame, the gravity sensor is connected with the singlechip, and the heating mechanism is connected with the singlechip. The feeding station, the detection and measurement station and the material removal station are circularly switched, the detection work is conducted continuously uninterruptedly, and the requirements on accurate and rapid measurement are met.