The present invention is a method to prepare sodium carbonate solution by flue gas recycling. Firstly the sodium hydroxide solution needed is prepared in a recycling groove and the sodium hydroxide solution prepared is infiltrated into a gas-liquid injector by recycling pump to react with the carbon dioxide in the flue gas generated by passing through a cooler. The sodium hydroxide solution prepared and the carbon dioxide react with a temperature between 50 to 90 degrees and carry through recycling reaction. When the reaction is terminated, the free alkali concentration in the recycling groove is more than 0 percent. The present invention has solved the greenhouse effect to atmosphere caused by carbon dioxide; simultaneously the present invention creates the sodium carbonate solution by carbon dioxide. The present invention has the advantages of low cost and energy consumption, etc. The present invention can be broadly applied to the sodium carbonate solution preparation by carbonatation of the flue gas generated by burning of coal and natural gas and is specifically suitable for being applied to chlor-alkali enterprises.