The invention discloses a preparation method of a layered transition metal compound quantum dot solution, the preparation method comprises the following steps: mixing a layered transition metal compound, an active agent and a solvent, stirring evenly, performing ultrasonic vibration for 2-24h, performing centrifugal separation or dialysis separation to obtain a supernatant or an infiltration liquid which is the nano-layered transition metal compound quantum dot solution, wherein the concentration of the layered transition metal compound is 1-150mg / ml, the concentration of the active agent is 0.5-10mg / ml, the layered transition metal compound is MOS2, MOTe2, WS2, WSe2 or WTe2, the active agent is a non-ionic surfactant or an ionic surfactant, and the solvent is one or a plurality substances from of water and organic solvents. The preparation method provided by the invention is simple in process, easy to operate, green, environmentally friendly, and suitable for industrialized production, is a method for preparation of a layered ultra small quantum dot solution, and can be used for preparation of an evenly-distributed ultra small quantum dot solution with a size of 1-2nm.