The steel cable internal shading transmission system mainly consists of components such as a geared motor, drive shaft, winding sleeve, drive cable, reversing pulley, and screen drive edge. Its principle involves the drive shaft being connected to the geared motor and the winding sleeve, with the drive cable passing through the reversing pulleys on both sides of the curtain beam and fixed and wound around the winding sleeve. When the output shaft of the geared motor rotates, the drive shaft drives the winding sleeve to turn, and the rotation of the winding sleeve moves the cable. The screen drive edge is connected to the cable. Therefore, when the geared motor rotates back and forth, the screen drive edge can achieve reciprocating motion. When one end of the shading cloth is fixed to the beam or column and the other end is fixed to the drive edge connected to the cable, the shading screen can be unfolded or retracted.