A method for measuring the varying specific heat capacity of an adiabatic reaction based on compensating power modulation, wherein: a dynamic heat loss of a sample in an adiabatic reaction is compensated in real time by additional heating to keep the sample in an ideal adiabatic environment in the reaction; characterized in that: a compensating power is modulated, that is, a cosine modulation term is loaded during the additional heating to realize oscillation of a temperature rise rate in the reaction; differential calculation and discrete Fourier transform are performed on an adiabatic reaction temperature of the sample in a modulated state, and a modulation temperature rise signal and a self-accelerating reaction temperature rise signal are separated to measure a varying specific heat capacity; the method specifically comprises the following steps: (a) measuring a specific heat capacity and a mass of a sample container, and a mass of the sample; (b) calculating a real-time power output of a compensating heater; (c) outputting Pulse-Width Modulation - PWM signals with different duty cycles by a temperature control module; (d) measuring a temperature change of the sample in the reaction; (e) differentiating the temperature change of the sample; and (f) solving the varying specific heat capacity according to the following formula where "Cs " is the varying specific heat capacity of the sample every x-seconds, "a" is the amplitude of the modulating power, "ω" is the angular frequency of the modulating power, "Cb " is the specific heat capacity of the sample container, "mb" is the mass of the sample container, "Δt" is temperature collection interval, "cp" is the phase angle, "ms" is the mass of the sample; and "A" is the modulus obtained by decomposing the x-second signal on the complex plane. a dynamic heat loss of a sample in an adiabatic reaction is compensated in real time by additional heating to keep the sample in an ideal adiabatic environment in the reaction; characterized in that: a compensating power is modulated, that is, a cosine modulation term is loaded during the additional heating to realize oscillation of a temperature rise rate in the reaction; differential calculation and discrete Fourier transform are performed on an adiabatic reaction temperature of the sample in a modulated state, and a modulation temperature rise signal and a self-accelerating reaction temperature rise signal are separated to measure a varying specific heat capacity; the method specifically comprises the following steps: (a) measuring a specific heat capacity and a mass of a sample container, and a mass of the sample; (b) calculating a real-time power output of a compensating heater; (c) outputting Pulse-Width Modulation - PWM signals with different duty cycles by a temperature control module; (d) measuring a temperature change of the sample in the reaction; (e) differentiating the temperature change of the sample; and (f) solving the varying specific heat capacity according to the following formula where "Cs " is the varying specific heat capacity of the sample every x-seconds, "a" is the amplitude of the modulating power, "ω" is the angular frequency of the modulating power, "Cb " is the specific heat capacity of the sample container, "mb" is the mass of the sample container, "Δt" is temperature collection interval, "cp" is the phase angle, "ms" is the mass of the sample; and "A" is the modulus obtained by decomposing the x-second signal on the complex plane. a compensating power is modulated, that is, a cosine modulation term is loaded during the additional heating to realize oscillation of a temperature rise rate in the reaction; differential calculation and discrete Fourier transform are performed on an adiabatic reaction temperature of the sample in a modulated state, and a modulation temperature rise signal and a self-accelerating reaction temperature rise signal are separated to measure a varying specific heat capacity; the method specifically comprises the following steps: (a) measuring a specific heat capacity and a mass of a sample container, and a mass of the sample; (b) calculating a real-time power output of a compensating heater; (c) outputting Pulse-Width Modulation - PWM signals with different duty cycles by a temperature control module; (d) measuring a temperature change of the sample in the reaction; (e) differentiating the temperature change of the sample; and (f) solving the varying specific heat capacity according to the following formula (a) measuring a specific heat capacity and a mass of a sample container, and a mass of the sample; (b) calculating a real-time power output of a compensating heater; (c) outputting Pulse-Width Modulation - PWM signals with different duty cycles by a temperature control module; (d) measuring a temperature change of the sample in the reaction; (e) differentiating the temperature change of the sample; and (f) solving the varying specific heat capacity according to the following formula where "Cs " is the varying specific heat capacity of the sample every x-seconds, "a" is the amplitude of the modulating power, "ω" is the angular frequency of the modulating power, "Cb " is the specific heat capacity of the sample container, "mb" is the mass of the sample container, "Δt" is temperature collection interval, "cp" is the phase angle, "ms" is the mass of the sample; and "A" is the modulus obtained by decomposing the x-second signal on the complex plane.