A parametric code transformation method for a gas water heater, wherein the gas water heater comprises a gas supply dial switch , and the parametric code transformation method comprises: acquiring (S1) dial state information of the gas supply dial switch , and determining a gas supply for the gas water heater according to the dial state information, wherein the gas supply for the gas water heater comprises natural gas and liquefied gas; transforming (S2) a parametric code of the gas water heater into a first parametric code, when the gas supply is the natural gas; characterized in acquiring (S3) a parametric code difference value and transforming the parametric code of the gas water heater into a second parametric code according to the first parametric code and the parametric code difference value, when the gas supply is the liquefied gas, and in that the parametric code difference value is acquired by: acquiring (S31) respectively first optimal parametric codes for a plurality of gas water heaters when supplied with natural gas and second optimal parametric codes for the plurality of the gas water heaters when supplied with liquefied gas; calculating (S32) a difference value between the first optimal parametric code and the second optimal parametric code for each of the plurality of the gas water heaters when respectively supplied with natural gas and liquefied gas; and calculating (S33) an average value of the difference values and taking the average value as the parametric code difference value. acquiring (S1) dial state information of the gas supply dial switch , and determining a gas supply for the gas water heater according to the dial state information, wherein the gas supply for the gas water heater comprises natural gas and liquefied gas; transforming (S2) a parametric code of the gas water heater into a first parametric code, when the gas supply is the natural gas; characterized in acquiring (S3) a parametric code difference value and transforming the parametric code of the gas water heater into a second parametric code according to the first parametric code and the parametric code difference value, when the gas supply is the liquefied gas, and in that the parametric code difference value is acquired by: acquiring (S31) respectively first optimal parametric codes for a plurality of gas water heaters when supplied with natural gas and second optimal parametric codes for the plurality of the gas water heaters when supplied with liquefied gas; calculating (S32) a difference value between the first optimal parametric code and the second optimal parametric code for each of the plurality of the gas water heaters when respectively supplied with natural gas and liquefied gas; and calculating (S33) an average value of the difference values and taking the average value as the parametric code difference value. acquiring (S31) respectively first optimal parametric codes for a plurality of gas water heaters when supplied with natural gas and second optimal parametric codes for the plurality of the gas water heaters when supplied with liquefied gas; calculating (S32) a difference value between the first optimal parametric code and the second optimal parametric code for each of the plurality of the gas water heaters when respectively supplied with natural gas and liquefied gas; and calculating (S33) an average value of the difference values and taking the average value as the parametric code difference value. <EOS>