Fluctuation temperature control method of gas water heater and gas water heater

The invention discloses a fluctuation temperature control method of a gas water heater and the gas water heater. The fluctuation temperature control method of the gas water heater comprises the following steps that S1, the gas water heater is started; s2, entering a constant temperature control program; s3, entering a temperature fluctuation stage; s4, the water pump operates according to the preset power P1; s5, judging whether a temperature rise stage is entered or not, and if yes, entering S6; s6, the power of the water pump is continuously reduced for n seconds, and the reduced power per second is (P1-Pmin)/n; s7, entering a highest temperature maintaining stage, wherein the maintaining time is 1/m1Y seconds; s8, the cooling stage is started, the power of the water pump continuously rises by 1/m < 2 > Y seconds, and the rising power per second is Pmax-Pmin/(1/m < 2 > Y); s9, entering a lowest temperature maintaining stage, wherein the maintaining time is 1/m < 3 > Y seconds; s10, entering a heating stage,