The invention discloses an agent for soil antibiotics resistance gene contamination reduction and preparation and application of the agent. A preparation method of the agent comprises the following steps that (1) at least one plant of dandelions, fig leaves, pineapple peels, roses, geraniums, lavender, pea hulls and rosemary is aired and then crushed, filtering is carried out after extraction, filter liquor and plant residues are collected, and the filter liquor is subjected to rotary evaporation to obtain natural plant crude extracts; and (2) 2-hydroxy-1,2-di-2-pyridylethanone, 2,5-diketopiperazine and the natural plant crude extracts are uniformly mixed according to the ratio to obtain a quorum sensing inhibitor, the plant residues and carbamide are mixed according to the ratio to obtain a soil improvement agent, the quorum sensing inhibitor and the soil improvement agent are uniformly mixed according to the ratio, and the agent can be obtained. The agent is directly applied to antibiotics resistance gene contaminated soil, or the agent is applied to the antibiotics resistance gene contaminated soil after being uniformly mixed with fertilizer, or the agent is applied to the antibiotics resistance gene contaminated soil before the fertilizer is applied.