The invention provides a front end guide limitation structure of a three-section sliding rail. By the front end guide limitation structure, the problems that an intermediate sliding rail is easy to be stuck during the process of installing an inner sliding rail of an existing three-section sliding rail onto the intermediate sliding rail and a ball seat is deformed due to impact on the ball seat can be solved. A positioning structure is arranged on a bottom plate at an end part of a front side of the intermediate sliding rail, a guide limitation piece is arranged in the positioning structure, an end surface of a front side of the guide limitation piece is flush with an end surface of the front side of the intermediate sliding rail, symmetric limitation parts are arranged at a left side and a right side of the guide limitation piece, outer side surfaces of the two limitation parts are respectively matched with inner wall surfaces of two side walls of the intermediate sliding rail, inner side surfaces are guide surfaces matched with two side wall surfaces of the inner sliding rail.