A door/window comprising an operating system with multiple locking points comprising: an inner frame and an outer frame of a door/window while the inner frame having four frame strips; a gear casing arranged at a first side of the inner frame and a handle used to control a drive bar, an exposed hinged corner device, and an opening mechanism through the gear casing so as to open the inner frame having a second side pivoted to the outer frame for tilt and inward opening of the door/window; the gear casing including a first casing and a second casing corresponding to each other; a gear controlled by the handle being mounted in the first casing and the second casing, and being used for driving a rack arranged at a moveable frame to slide and move; the door/window is opened or closed according to changes of sliding positions of the moveable frame connected with the first casing and the second casing; wherein the first casing and the second casing of the gear casing are corresponding to each other and made from plastic, characterized in that the first casing is disposed with at least one insertion hole while the second casing is arranged with at least one bored connecting rod projecting from an inner surface thereof; the bored connecting rod is corresponding to the insertion hole and the number of the projecting bored connecting rod is the same with the number of the insertion hole; a plurality of grooves is arranged annularly around the bored connecting rod and the grooves allow tightening pieces to be expanded outwards and elastically deformed while being applied with forces; thereby the bored connecting rod is inserted into the insertion hole to connect the first casing and the second casing smoothly after internal components of the gear casing being mounted and positioned into the first casing and the second casing; a positioning pin is passed through the insertion hole and inserted into the bored connecting rod after the first casing and the second casing being connected; and the positioning pin presses the tightening piece to expand outward so as to make the bored connecting rod fit in the insertion hole of the first casing tightly. an inner frame and an outer frame of a door/window while the inner frame having four frame strips; a gear casing arranged at a first side of the inner frame and a handle used to control a drive bar, an exposed hinged corner device, and an opening mechanism through the gear casing so as to open the inner frame having a second side pivoted to the outer frame for tilt and inward opening of the door/window; the gear casing including a first casing and a second casing corresponding to each other; a gear controlled by the handle being mounted in the first casing and the second casing, and being used for driving a rack arranged at a moveable frame to slide and move; the door/window is opened or closed according to changes of sliding positions of the moveable frame connected with the first casing and the second casing; wherein the first casing and the second casing of the gear casing are corresponding to each other and made from plastic, characterized in that the first casing is disposed with at least one insertion hole while the second casing is arranged with at least one bored connecting rod projecting from an inner surface thereof; the bored connecting rod is corresponding to the insertion hole and the number of the projecting bored connecting rod is the same with the number of the insertion hole; a plurality of grooves is arranged annularly around the bored connecting rod and the grooves allow tightening pieces to be expanded outwards and elastically deformed while being applied with forces; thereby the bored connecting rod is inserted into the insertion hole to connect the first casing and the second casing smoothly after internal components of the gear casing being mounted and positioned into the first casing and the second casing; a positioning pin is passed through the insertion hole and inserted into the bored connecting rod after the first casing and the second casing being connected; and the positioning pin presses the tightening piece to expand outward so as to make the bored connecting rod fit in the insertion hole of the first casing tightly.