The invention discloses a dispersant proportioning device and a proportioning method for granule test, comprising a support base, a glass tank, a water tank, a hanging wire, a dispersant storage container, a tray and a measuring cylinder, the support base is fixed with a support vertical frame, the support vertical The top of the frame is fixed with a horizontal bracket, the top of the suspension wire is fixed on the horizontal bracket, the bottom end of the suspension wire is fixed at the center of the tray, and the bottom of the tray center is fixed with a horizontally arranged sealed glass tube. The inner cavity of the sealed glass tube is sealed and filled with liquid. There is a bubble in the liquid of the glass tube, the bottom of the measuring cylinder is connected to the conduit A, the bottom of the dispersant storage container is connected to the conduit B, the top of the support seat is equipped with a motor and a rotating shaft seat, and the center of the bottom of the glass jar is fixed with a rotating shaft. The bottom is communicated with a right conduit, the water tank is placed on the platform to be provided with a water tank, and the bottom of the water tank is communicated with a water delivery pipe. The invention can realize the high-efficiency proportioning of the dispersant used in the particle test, improves the safety of the test, and thus improves the level of scientific research.