Disclosed is a timing guide rail. The timing guide rail comprises a support, a guide strip and an elastic element. The support is used for fixing installation. The guide strip is installed on the support in a slidable mode. A first guide sliding surface and a second guide sliding surface are arranged on the same side of the guide strip, are used for limiting a chain, and are in smooth transition. The first end of the elastic element is connected with the support, and the second end of the elastic element is connected with the guide strip. By the adoption of the timing guide rail, the position of the guide strip can be automatically changed according to the difference of the speed of the chain so that the chain can be limited in the mode of a more appropriate molded line.