The invention discloses a polymer dispersed liquid crystal random laser device, and a preparation method and a control method thereof. The polymer dispersed liquid crystal random laser device comprises a glass substrate, a mylar, dye nematic liquid crystal microdroplets and a polymer, wherein laser dye and nematic liquid crystals are ultrasonically mixed to form a dye nematic liquid crystal mixed solution, the dye nematic liquid crystal mixed solution and photo-polymerization monomers are mixed according to a certain weight ratio, and heated and stirred uniformly so as to form a homogeneous solution, the homogeneous solution is poured into a base box container so as to be solidified and form a random laser device, pump light is used to vertically irradiate the surface of the random laser device, random lasers can be observed in the side direction of the random laser device, the random laser device is symmetrically and uniformly sheared through a mechanical platform along the long edge direction of the random laser device, and then intensity of the pump light is kept unchanged, the shearing distance is controlled, intensity of the random lasers changes along with the shearing distance, and when the shearing distance reaches a certain threshold value, the random lasers are switched off. The polymer dispersed liquid crystal random laser has the advantages of being low in cost, simple in structure, convenient to achieve and the like.