The invention discloses a saloon car safety belt test auxiliary device which aims to overcome the problems that when a saloon car safety belt test is completed in an existing saloon car safety belt test auxiliary device, a fabricated chest model installing device is inadequate. The saloon car safety belt test auxiliary device comprises a clamping mechanism (2), a decelerating mechanism (4), a lifting motor (6), an outer shell (12), a lifting sliding sleeve (15), and a gear rack (19), wherein the upper end of a lead screw (14) which is installed inside the outer shell (12) is connected with the top end of the outer shell (12) in a rotating mode, the top end of the lead screw (14) is connected with the lifting motor (6), a screw (16) is installed on the lead screw (14) in a sleeved mode, the lifting sliding sleeve (15) is sleeved on the outer shell (12) to be connected in a sliding mode, a sliding rod (18) is fixed outside the lifting sliding sleeve (15), and the gear rack is fixed on the inner side of the sliding rod (18). Besides, the decelerating mechanism (4) is fixed on the right side of the lifting sliding sleeve (15), a toothed gear (21) of the decelerating mechanism (4) is meshed with the gear rack (19), and the clamping mechanism (2) is fixed on the outer side face of the sliding rod (18).