The invention provides a chemical method for trapping, chemically fixing and purifying greenhouse gases such as carbon dioxide, sulfur dioxide, sulfur trioxide, nitrogen oxides and the like, which is characterized by adopting an organic metal compound and a solvent as trapping and chemical fixing agents, wherein the organic metal compound is a coordination compound of nitrogenous organic bismuth and organic antimony; and the solvent is an organic solvent. By means of the method, the trapping and chemical fixing of all the greenhouse gases can be realized to form corresponding metal salts; and at different temperatures, selective gradient analysis can be realized so that the trapping and purification of single gas is further realized. The trapping and fixing agents have high fixing capacity, high analytic speed, low regeneration energy consumption and low price, are easy and simple to prepare, have high stability and can be used repeatedly. The chemical method can be widely used for carrying out trapping and chemical fixing on the greenhouse gases in flue gas, synthesis ammonia, natural gas, kiln gas and the like and can realize enrichment purification of the single gas in one step.