The invention belongs to the field of the additive manufacturing correlation technique, and discloses a laser selective melting forming device and method. The forming device comprises an industrial personal computer, a magnet exciting coil set, an electronic voltage adjuster, an adjustable resistor, a single-chip microcomputer, an ultrasonic power source and an ultrasonic vibration device. The magnet exciting coil set comprises multiple magnet exciting coils, and the multiple magnet exciting coils and the ultrasonic vibration device are arranged around a substrate of a forming cavity during use. The magnet exciting coils are connected with the industrial personal computer and the adjustable resistor, and the electronic voltage adjuster is connected with the magnet exciting coils and the adjustable resistor. The ultrasonic power source is connected with the single-chip microcomputer and the ultrasonic vibration device. The single-chip microcomputer is further connected to the electronicvoltage adjuster. The industrial personal computer is used for controlling the angle and on-off of the magnet exciting coil set according to different laser scanning phase angles so as to achieve zoning control of a magnetic field. The single-chip microcomputer is used for controlling the amplitude and frequency of the ultrasonic vibration device. According to the laser selective melting formingdevice and method, high-performance laser selective melting forming is achieved, and structure consistency is improved.