The invention provides a method for preparing a controlled-release nano-pesticide preparation. The method comprises the following steps: emulsifying components of the nano-pesticide preparation to form an initial emulsion; and then performing high-pressure homogenization to form a fine emulsion to prepare a wall-material-coated nano-pesticide preparation. The method is simple, easy to operate and good in repeatability, and the prepared nano-pesticide preparation is small in grain size, favorable in grain dispersity and excellent in controlled-release performance.