The invention discloses a device of an external skeleton rehabilitation mechanical arm with five independent-motion fingers and a method. The device comprises an external skeleton mechanical arm body,a control system, linear motors, a thumb three-dimensional position sensor and a pressure sensor. The six linear motors control different mechanical units respectively and are arranged on a palm backplatform, all the linear motors on the four fingers drive all the mechanical units on the four fingers to move independently, a thumb dual-linear motor assists in control over motion of the externalskeleton thumb, and the thumb three-dimensional position sensor is installed at the tail end of a thumb far-end finger sleeve and feeds back the position of the tail end of the thumb in the operationof the linear motors in real time; the pressure sensor is fixed to the far-end finger sleeve of the external skeleton index finger mechanical unit, corresponds to the position of the finger pulp of the far-end knuckle of the index finger of a user and measures the pressure of the index finger at the position, and the control system receives collection data. In combination with position signals ofthe linear motors and position signals of the thumb three-dimensional position sensor, motion and/or stopping of all the linear motors are controlled.