Abstract: A mounting rod assembly for installing a curtain has a main rod and a telescopic rod; one end of the telescopic rod stretches into the main rod and can slide along the length direction of the main rod, and the main rod is provided with a locking member for stopping the sliding of the telescopic rod; through the cooperation of the telescopic rod and the main rod, the entire mounting rod assembly can be fitted to the window frames of various sizes during installation. The installation length is adjusted by adjusting the length of the telescopic rod extending out of the main rod, and then locking and positioning the telescopic rod with the locking member, which makes the curtain more applicable and the installation more flexible.