The invention discloses a noise-immunity adaptive-compensation terahertz optical comb spectrum detection method. The method comprises: repeated frequencies of two femtosecond laser sources are locked by using a feedback regulation method to obtain two optical combs; beat processing is carried out on two optical comb signals and two continuous optical signals and a series of signal processing is carried out to generate an adaptive compensation signal and a signal acquisition clock signal; one optical comb is used as pump light to generate a terahertz optical comb and the other optical comb is used as detection light, and a voltage signal reflecting a terahertz electric field is obtained from a semiconductor antenna; carrier envelope drift compensation is carried out on the electric signal by the compensation signal and then the clock signal is used for signal collection. With the method, the robustness of the terahertz optical comb spectrum system is improved; the high measurement precision is realized in a wide spectral range; and a signal to noise ratio of a sampling system is increased.