The invention discloses a volume variable air spring auxiliary chamber experiment device and a volume variable air spring auxiliary chamber experiment method. Inner cavities of a cylindrical shell of an auxiliary chamber are eight sector cylinder chambers with same volume, which are separated by sector plates circumferentially; a clapboard is enclosed on the upper end face of the eight sector cylinder chambers, and is provided with eight small holes opposite to the eight sector cylinder chambers; a movable cover plate is arranged on the upper layer of the cylindrical shell, and is provided with a height sensor; the lower end face of the movable cover plate is vertically fixedly connected with eight plunger pistons respectively in sealed fit with the eight small holes, and the lengths of the eight plunger pistons form an arithmetic progression in turn; an air spring system is connected with a computer through a numerical control electrohydraulic servo vibration testing system; and withthe increase of the heights of the eight plunger pistons, the eight sector cylinder chambers are opened in turn, the influence of different volumes of the auxiliary chamber on the characteristics of the air spring is measured, the air spring can obtain a wider rigidity change range, and the running stability and riding comfortability of a sedan are improved.