The invention relates to a mobile power supply that can be charged externally and can be self-charged. It consists of an elastic hand-held pressure handle, a fixed bracket for a power generation device, a first convex gear, a straight rack push rod with opposite tooth directions on adjacent two sides, and a fixed button. , fixed shaft support, rack positioning hole, mobile power supply shell, second convex gear, first power generation device, second power generation device, lock switch, emergency USB interface, rectification and voltage stabilization circuit, etc. The mobile power supply shell is equipped with Emergency USB interface, elastic hand grip pressure handle, etc., the first power generation device and the second power generation device are perpendicular to each other, and the convex gears set on the fixed shafts of the respective power generation devices and the straight rack push rods with opposite tooth directions on the adjacent two sides Corresponding to the meshing, the output of the first power generation device and the second power generation device are respectively connected to the input end of the first rectification circuit and the input end of the second rectification circuit. Provide power to mobile devices such as mobile phones.