The invention discloses a chlorate oxygen candle with stable combustion for oxygen supply and a preparation method of the chlorate oxygen candle. The chlorate oxygen candle comprises a main candle body and a combustible medicine layer, wherein the main candle body is prepared from, by weight, 70-88 parts of sodium chlorate, 1-15 parts of potassium perchlorate, 2-6 parts of fuel, 0.5-5 parts of acatalyst, 1-8 parts of a chlorine inhibitor, 1-8 parts of a binder and 2-5 parts of a broken metal piece; the combustible medicine layer is prepared from, by weight, 75-86 parts of sodium chlorate, 1-5 parts of potassium perchlorate, 2-10 parts of fuel, 1-5 parts of a catalyst, 2-8 parts of a chlorine inhibitor and 0.5-4 parts of a broken metal piece. The preparation method includes the steps: preparation of the main candle body, namely evenly dry-blending the raw materials added with 0.5% of distilled water by evenly wet-blending; preparation of the combustible medicine layer, namely evenlydry-blending the raw materials added with 0.5% of distilled water by evenly wet-blending; loading a mould press between positions under the main candle body and above the combustible medicine layer for compression molding prior to placing in an oven for 14 hours at 120-140DEG C after demolding. The chlorate oxygen candle is good in heat-transfer performance, and heat generated from combustion cannot be accumulated to cause combustion to increase; post-combustion residues are less prone to flow, and stable combustion for oxygen supply is guaranteed.