The invention discloses a safe and environmental-friendly fresh keeping agent for foods. The safe and environmental-friendly fresh keeping agent is prepared from two raw materials of dandelions and aqueous solubility chitosan. The dandelion flavonoids contain various flavonoids, have the effects of restraining mould, fungi, bacteria and protozoa, are in cooperation with the chitosan for use, can effectively separate air, have favorable bacterial inhibition properties, and are good in sterilizing effect. The operation is simple, the raw material sources are extensive, the cost is low, and the safe and environmental-friendly fresh keeping agent is easy to popularize.