The invention discloses a servo upset-extruding molding device and method. The device is mainly composed of an upset-extruding molding device, a hydraulic device host, a servo control system and the like; the upset-extruding molding device has functions of vertical extruding and mold locking, horizontal upsetting and force increasing, mold assembly leveling and positioning, upset-extruding mold expansion prevention and shape correction, precise and synchronous control and the like; a vertical crank staggering and horizontal upsetting cavity is a combined cavity, the crankshaft upset-extruding molding technology can be achieved, defects of mold mistaking, nicking, unfilled and warp filling of two ends of the inner side of a crank handle plate and the like in the process of crankshaft mold assembly, upset-extruding molding and mold releasing can be effectively overcome, and the crankshaft filling effect, the coaxiality and the fiber continuity are improved. The device and method can be applied to upset-extruding molding of vehicle crankshafts, ship crankshafts and various non-symmetric crank handle plate thickness crankshafts.