The invention relates to a magnetic adsorption device and a searchlight comprising the magnetic adsorption device. The magnetic adsorption device comprises a magnet, a fixing base and a magnetic switch for enabling/disabling the magnet to produce adsorptive force; the searchlight comprises a lamp cap, a main body, a chassis and at least a magnet arranged on the chassis, at least a part of the magnet is equipped with a magnetic switch for enabling/disabling the magnet to produce adsorptive force. The magnetic switch comprises two magnetic conductors fixed on the fixing base and a rotary member arranged on the magnet for rotating the magnet; a non-closed loop which has circular inner wall with two symmetrical notches is formed by arranging symmetrically the two magnetic conductors at a certain distance; the magnet, being cylindrical, is capable of rotatably being installed on the fixing base and positioned in a cavity formed by the inner wall of the non-closed ring. The invention is capable of disassembling the magnetic adsorption device or the searchlight from a carrier without scratching or deforming the surface of the carrier.