A control system and teaching method for a seven-axis articulated robot are provided, which system and method are capable of easily grasping a motion trajectory of the whole robot and thereby performing proper teaching during teaching operation. The control system includes a setting device for setting a specified plane in a teaching mode for teaching a seven-axis articulated robot; a control unit for controlling the movement of the seven-axis articulated robot so as to restrict a motion trajectory of an elbow portion within the plane set by the setting device; and a computing unit for performing inverse transform operation to calculate the pivot angle of each pivot axis based on a change in a position of the hand end, setting the restriction of the movement of the elbow portion as a constraint condition, when the position for the hand end is taught.