Ultrasonic vibration is introduced to the process of laser metal forming IN718, the surface roughness, residual stress, and mechanical property at room temperature of the forming parts are tested, and the microstructure of the forming parts is analyzed. The results show that, after the introduction of ultrasonic vibration, the surface roughness degree and residual stress of the forming parts are remarkably improved, the microstructural refinement is obtained, and the tensile strength and yield strength are both increased. When the ultrasonic power is 44 W and the ultrasonic frequency is 17 kHz, compared with those of the parts without experiencing ultrasonic vibration, the residual stresses along x direction and y direction respectively decrease by 47.8% and 61.6%, the yield strength, tensile strength and area reduction increase by 6.1%, 2.7% and 10.6%, and the elongation slightly decreases to 29.2%.