The invention relates to the technical field of purification of marsh gas, and in particular relates to a method and equipment for preparing and storing high-quality natural gas from marsh gas. The method comprises the following steps: pumping marsh gas, and performing primary filtration on the marsh gas; then, feeding the marsh gas a refrigeration dryer, and initially drying the marsh gas; feeding dried gas into secondary and tertiary filters and purifying, wherein the filtration precision achieves 0.01 mu m, and the filtering efficiency achieves 99.999%; after pre-processing, heating the feed gas through a heat exchanger and feeding the feed gas into a membrane separation system, and removing most of acid gas is removed, thereby obtaining methane having higher purity; after pressurizing through a compressor, introducing the methane into a pressure swing adsorption system and purifying methane deeply, thereby obtaining methane with the purity of not less than 98%; introducing methane into a high-pressure stirring type reaction kettle, so as to generate steady gas hydrate; and storing natural gas. By means of the method and the equipment disclosed by the invention, methane can be purified and prepared from marsh gas (or marsh gas like air sources); therefore, emission of greenhouse gases is reduced; and waste recycling is realized.