The utility model relates to an improvement of the structure of a program switch, particularly a sliding block to improve the traditional program switch when dialing. The sliding block body is easy to be squeezed by a salient point of an upper cover, and leading to wear the sliding block body and the salient point. The utility model is mainly composed of a subbase, the upper cover and the sliding block. The program switch is characterized in that spacing salient points are respectively arranged on the two corresponding sides of a frieze; blocking ends are formed at the ends of the both sides of the sliding block, and a concave part is opened between the two blocking ends, forming the pattern which is symmetrical and convex extension outwards. A positioning column which is supplied for fixing a contacting guide vane is arranged under the body. The utility model assuredly has assured positioning, and the utility model can increase the service life of the contacting guide vane and improve the disadvantage that the sliding block body is easy to be squeezed by the salient point of the upper cover and the track is offset.