The invention belongs to the field of edible fungus fresh keeping, and particularly relates to a needle mushroom fresh-keeping agent and a preparation method thereof. The needle mushroom fresh-keepingagent is prepared from the following raw materials in parts by weight: 3 to 6 parts of folium artemisiae argyi, 10 to 15 parts of yellow cinnamon leaves, 3 to 6 parts of lotus leaves, 6 to 10 parts of fructus chebulae, 3 to 6 parts of rhizoma polygoni cuspidati, 3 to 6 parts of radix paeoniae rubra, 2 to 4 parts of rhizoma anemarrhenae, 3 to 6 parts of green tea, 6 to 10 parts of radix arnebiae seu lithospermi, 3 to 6 parts of herba andrographitis, 8 to 12 parts of Ilex pur-purea buds, 3 to 6 parts of herba arabidopsis thalianae, and 2 to 4 parts of pears. The raw materials are classified into three types according to the effect of raw materials and are extracted by separately utilizing a water decoction extraction method, a methanol extraction method, and an ethanol reflux method, and then the obtained extraction solutions are mixed and fermented, thus obtaining the needle mushroom fresh-keeping agent. By adopting the needle mushroom fresh-keeping agent provided by the invention, the growth proliferation of microorganisms can be inhibited, the breathing and metabolism effect of the needle mushrooms can be alleviated, the needle mushrooms can be effectively kept fresh, and the fresh-keeping period can be 40 days or more; and moreover, the needle mushroom fresh-keeping agent is wide in raw material source, simple in preparation method and low in cost.