The invention discloses a sash window sectional bar which comprises a front plate, a rear plate, a connecting plate, a lower clamping groove, a lower sliding rail, an upper sliding rail and an upper clamping groove. The front plate and the rear plate are each designed into an L-shaped structure, the stability of the sectional bar fixedly installed inside cement is ensured, the connecting plate isused for connecting the front plate with the rear plate and enhancing the strength of the whole aluminum profile, the lower clamping groove is formed in the middle position, the upper clamping grooveis formed in the rear plate, and the lower sliding rail and the upper sliding rail are arranged on the two sides of the connecting plate; the aluminum profile is provided with the corresponding clamping grooves in the lower sliding rail and the upper sliding rail, meanwhile, the clamping grooves are designed to be of the wrapping type structure, the clamping grooves are used for containing sponge,the wear resistance and waterproof type of the aluminum profile in the using process are ensured, meanwhile, due to the L-shaped front and rear plates with reinforcing ribs, the installation convenience of the aluminum profile is ensured, the strength of the aluminum profile is ensured, and the aluminum profile has the certain application and popularization value.