The utility model discloses a multimedia teaching technical field's a multimedia teaching projecting apparatus based on computer technology, the large -scale motor assembly jig comprises an operationbench, control computer is installed on the top right side of operation panel, there is motor control switch in the top left side of operation panel through the screw connection, there is the supporting leg on the bottom right side of operation panel through the screw connection, there is the cabinet body in the bottom left side of operation panel through the screw connection, the left side wall bottom of the cabinet body is connected with accommodate motor through the motor cabinet, the control circuit that motor control switch passes through wire and accommodate motor is connected, there isthe screw rod at the top of accommodate motor output shaft through the coupling joint, the left side wall upside of the cabinet body has sharp sliding sleeve through the screw connection, it has the support frame vertically to run through in the straight line sliding sleeve, this multimedia teaching projecting apparatus based on computer technology, and through electromechanical control mode, theconvenience is highly adjusted the projection screen, improves the visibility of projection screen.