Abstract: The present invention provides a universal tool extension rod, including a plurality of universal coupling sleeves and first and second end joints. A corresponding polygonal sphere and polygonal driver are mated between universal coupling sleeves, and the polygonal sphere can slide within the polygonal driver in straight mating or universally flexible states. The first and second end joints can be linked with the universal coupling sleeves similarly, so that the tool extension rod can be combined into a straight state or unhinged into a universally bending state where necessary. Both operating states can realize universality, robustness and durability due to multi-angle ability, high torsion and extensibility.