The utility model relates to a cylindrical LED square lamp. The cylindrical LED square lamp comprises a radiator and a mounting snap spring. The cylindrical LED square lamp is characterized in that the radiator includes a mounting framework, and one or more radiating blocks fixed on the mounting framework; the radiating blocks are connected with each other to form a concave surface among the radiating blocks; and the mounting snap spring is arranged on the mounting framework. The cylindrical LED square lamp also includes a reflective cover arranged in the concave surface and attached to the concave surface, an aluminum substrate positioned at the bottom part of the reflective cover and fixedly connected with the bottom part of the radiator, an LED on the aluminum substrate, a wiring box arranged outside the radiator, and a light penetrating cover located at the opening of the reflective cover, wherein the reflective cover has a cross section in the shape of Chinese character 'Ba'; the wiring box is electrically connected with the LED; and the light penetrating cover is movably and fixedly connected with radiator through a clamp device in a detachable manner. The cylindrical LED square lamp has the advantages of lower energy consumption, good appearance, low cost, rich color, and so on.