The invention provides an electro-dynamic tether based satellite deorbit device and a method thereof, relating to the satellite deorbit device and the method thereof. The device and the method solve the problems of high deorbit cost of a propellant deorbit method and low deorbit efficiency of an atmospheric drag deorbit method. In the system, a control signal output end of a control module is connected with a control signal input end of a tether releasing and reclaiming device; the tail end of an insulating tether section of the tether is fixed on the tether releasing and reclaiming device; and the tail end of a conductive tether section of the tether is connected with an electron collection transmitter. The method comprises the following steps: determining longitude, latitude and height of the position of a satellite at current time according to six factors of the initial orbit of the satellite to acquire the magnetic field strength of the current position; calculating the Lorentz force generated by the tether; resolving the Lorentz force along the radial direction, the tangential direction and the outerplanar direction to acquire the orbit six factors at next time, and determining a new height of the satellite orbit; and circulating the steps until the height of the satellite is less than or equal to 120km to complete the satellite deorbit process. The device and the method are applicable to the satellite deorbit process.