The invention provides a method for preparing and processing a cultivation medium. The method comprises the following steps: firstly, closely restraining the sources of raw materials and requiring that all raw materials are pollution-free and have no noxious residual and that the raw materials can be fetched from pollution-free mountains; secondly, disinfecting and sterilizing the raw materials, namely, blending the raw materials with a chemical agent which does not produce noxious residual first for stack retting and then thinly spreading the raw materials to be under the blazing sun for 3-7 days or longer, or blending the raw materials with a chemical agent which does not produce noxious residual without stack retting and then sealing the raw materials with a light transmissible material and thinly spreading the raw materials to be under the blazing sun for 3-7 days or longer; mixing treated soil, an organic fertilizer and other non-chemosynthetic and noxious residual-free fertilizer which is added depending on the circumstances, thereby obtaining the cultivation medium, specifically as follows in percentage by volume: not lower than 50% of treated soil, not higher than 20% of other non-chemosynthetic and noxious residual-free fertilizer which is added depending on the circumstances, and the balance of organic fertilizer. The method is capable of preparing the pollution-free and noxious residual-free cultivation medium by using local materials for ecological green cultivation, and is simple and convenient.