Abstract: A telescopic curtain guide rail includes an inner rail, an outer rail and a transmission unit. The inner rail is embedded in the outer rail, the transmission unit includes a driving wheel connected with a motor, a driven wheel, two fixed pulleys and a conveyor belt. The driving wheel and the driven wheel are located at two ends of the curtain guide rail, the two fixed pulleys are respectively located at other ends of the inner rail and outer rail. The driving wheel and one fixed pulley are located at two ends of the inner rail or outer rail, the conveyor belt is wound on the driving wheel, the driven wheel and the two fixed pulleys. A telescopic operation of the curtain guide rail can change positions of the two fixed pulleys simultaneously, and the curtain guide rail is simple to use and has a small occupied area.