The invention discloses a low-friction timing chain transmission device. The low-friction timing chain transmission device comprises a timing chain and a positioning guide rail used for limiting the moving track of the timing chain. The positioning guide rail comprises an upper guide rail, a fixed guide rail and a movable guide rail. The concavity of the upper guide rail is 1-3%. The concavity ofthe fixed guide rail is 3-6%. The concavity of the movable guide rail is 6-13%. According to the scheme, the concavity of the face, in contact with the chain, of the positioning guide rail is optimized, so that the positive pressure is greatly reduced when the chain makes contact with the positioning guide rail, and accordingly, the friction resistance is effectively reduced, and the friction lossis reduced.