The invention discloses an auxiliary fixing device used for model making. The auxiliary fixing device comprises a bottom plate, a fixed seat, a rotary knob, a lead screw, a clamping plate, a sliding rod, an inclined overturning mechanism and buffering mechanisms. The inclined overturning mechanism is arranged at the upper end of the bottom plate, an electric push rod is powered on to work, a fixedplate drives a sliding seat to move at the upper end of a guide rail, the sliding seat drives a gear to rotate through a rack, and a rotating shaft drives the fixed seat to rotate, so that the inclination position of a part is changed, and the advantage of quickly adjusting the inclination angle of the part is achieved; the buffering mechanisms are arranged at the front end and the rear end of the fixed seat, when the fixed seat inclines, a pressing rod can be driven to move on the inner side of a stand column, the pressing rod drives a buffering spring to deform, and therefore the fixed seatinclines stably, and the advantage that the fixed seat can be adjusted stably is achieved.