Focusing control system applied to spaceborne camera and focusing control method

A focusing control system applied to a spaceborne camera and a focusing control method relate to the spaceborne mechanism control system design field. The system comprises a stepping motor, a stepping motor driving circuit and a camera focal plane. The system is characterized in that the system also comprises an ARM microprocessor and a rebound-type magnetic linear displacement sensor; the rebound-type magnetic linear displacement sensor is vertically installed behind the camera focal plane, acquires a simulation voltage during camera-focal-plane linear movement and transmits the simulation voltage to the ARM microprocessor; the ARM microprocessor calculates a rotation step number and direction information of the stepping motor according to a camera focal plane preset position sent by a center machine and then sends a driving signal to the stepping motor driving circuit so that the camera focal plane arrives at a pre-focusing position; and the ARM microprocessor realizes closed loop focusing and open loop foc