The invention provides a single-layer two-dimensional material prepared on the surface of a micro-nano optical fiber and a light activation method thereof, belonging to the field of single crystal synthesis. The invention provides a method for preparing the single-layer two-dimensional material prepared on the surface of the micro-nano optical fiber based on a chemical vapor deposition method, andthe method comprises the following steps: placing the drawn micro-nano optical fiber on the bottom of an inverted Quartz boat, placing the drawn micro-nano optical fiber in a tubular high-temperaturefurnace, and adjusting to a proper growth program to grow the single-layer two-dimensional material on the surface of the optical fiber with the diameter of 0.3mu m to 20mu m; and after light activation treatment, the quantum efficiency can reach 30%. The method is simple, efficient and low in cost. The prepared two-dimensional material on the surface of the optical fiber has good surface qualityand high luminous efficiency, and has potential application value in the fields of coherent light sources, nonlinear optics, optoelectronics and the like.