The invention relates to a method using starch low-temperature reduction to prepare sodium sulfide. The method includes: simultaneously adding sodium sulfate and starch into a conical mixer, stirring and mixing, continuously conveying the mixed material to an indirect-heating reduction pot, heating to required temperature for reaction for a certain period of time, and dissolving, filtering, concentrating and crystalizing the reduction product to obtain the sodium sulfide. The method has the advantages that the starch is used as the reducing agent under an indirect heating condition, the sodium sulfide is produced by the low-temperature reduction of the sodium sulfate, the reduction rate of the sodium sulfate reaches above 98.0%, the reduction temperature is lowered from traditional 1000 DEG C to 800-850 DEG C, and energy consumption of sodium sulfate reduction is lowered greatly.