A method for analyzing the liquefied petroleum gas includes the following steps. Provide a sample of the liquefied petroleum gas, and one main component group of the liquefied petroleum gas includes at least one sub component group. Analyze the sample of the liquefied petroleum gas so as to obtain a first measured THC corresponding to the main component group and a second measured THC corresponding to the sub component group. Obtain a regressed THC according to the second measured THC and a predetermined relationship of THC. Obtain a result of THC according to the first measured THC, the regressed THC, and a predetermined range of THC. The predetermined range of THC corresponds to the main component group. The device for analyzing the liquefied petroleum gas includes an inlet, a multiposition valve, a first column, a second column, an analyzing apparatus, and a computing unit.