The invention relates to a method of efficiently preventing and treating injurious insects and harmful mites of leaf vegetables by natural enemies, and is characterized by being a method of preventing and treating the injurious insects and the harmful mites of the leaf vegetables by the natural enemies of the injurious insects and the harmful mites. The method comprises the following steps: investigation of the injurious insects and the harmful mites, preparation before release of the natural enemies, release of the natural enemies, investigation of a natural enemy release effect, and continuous release of the natural enemies according to the release effect, the temperature, the humidity and the planting requirement, wherein the steps are repeated until no natural enemy is released. By use of the method of preventing and treating the injurious insects and the harmful mites of the leaf vegetables, efficient utilization of the natural enemies can be realized; compared with other methods, the method disclosed by the invention has the advantage that the preventing effect can be enhanced by over 50 percent or even 100 percent; if the method is not used, the preventing effect is probably zero.