The invention discloses a surface treatment method of a natural organic filler utilizing a coupling agent vaporization principle, which comprises the following steps of: 1) determining the use amount of a coupling agent according to the use amount of the natural organic filler and drying the natural organic filler; 2) placing the coupling agent on the bottom of a container, placing the natural organic filler on a partition plate and covering with a sealing cover; 3) adjusting the temperature of a temperature-controllable heating plate to above the vaporization temperature and below the decomposition temperature of the coupling agent, placing the container on the temperature-controllable heating plate after the temperature is constant, and taking out the natural organic filler after the coupling agent is completely vaporized; and 5) plastifying and shaping the vaporized natural organic filler and a synthetic resin. The surface treatment method has good treatment effects that: the vaporized coupling agent may significantly increase the contact surface with the natural organic filler, thus improving the surface treatment effect; and the surface treatment method has the advantages of low manufacturing cost, easy material discharge, low filler loss and high applicability, and the surface treatment method has no limit on the treatment amount of the natural organic filler and is applicable to a small amount of the natural organic fillers that can not be treated by a high-speed mixer.