This paper presents a design scheme of an adaptive laser cladding robot for the inner wall of variable diameter pipes. The robot is in the shape of a capsule, with an adaptive walking system, a mechanical support and balance system, a laser cladding system and a water cooling system, which can achieve efficient laser cladding and strengthening of the inner walls of different pipes. Among them, innovative designs such as pressure overload protection device and beam focusing lens adjustment motor have significantly improved the stability and accuracy of robot operation. Compared with traditional equipment, the robot is simple in structure, easy to disassemble, reliable in performance, high in automation, easy to maintain, and low in energy consumption. It provides an effective solution for laser cladding of pipe inner wall under complex and changeable working conditions, and helps to promote the wide promotion and application of laser cladding technology.