A power semiconductor package device and a method of preparation the device are disclosed. The package device includes a die paddle, a first pin, a second pin, and a semiconductor chip attached to the die paddle. A first electrode, a second electrode and a third electrode of the semiconductor chip are connected to the first pin, the second pin and the die paddle respectively. A plastic package body covers the semiconductor chip, the die paddle, the first pin and the second pin. The first pin and the second pin are located near two adjacent corners of the plastic package body. The bottom surface and two side surfaces of each of the first pin and the second pin are exposed from the plastic package body. Locking mechanisms are constructed to prevent the first pin and the second pin from falling off the power semiconductor package device during a manufacturing cutting process. Portions of the first pin, portions of the second pin, and portions of the plastic package body can be cut off. Therefore, the size of the power semiconductor package device is reduced.