The invention relates to a nuclear magnetic resonance detection method for the composition of an isomer mixture, and the method is characterized in that the nuclear magnetic resonance detection methodis used for rapidly analyzing and identifying each component signal according to different chemical shift value distributions of each component signal in the isomer mixture in a one-dimensional purechemical shift hydrogen spectrum; and after a one-dimensional pure chemical shift spectrum is used for carrying out signal identification and analysis on the isomer mixture, molecular signals which belong to the a single component with an excited proton are extracted by means of chemoselective filtering an exciting pulse, and identification and analysis are further carried out on overlapping signals in the one-dimensional pure chemical shift spectrum, thereby realizing the effective analysis of each component of the isomer mixture. According to the nuclear magnetic resonance detection method,a sample is not required to be pretreated, a non-overlapping decoupled hydrogen spectrum of mixture components and a selective filtering experiment excitation spectrum of the single component can be obtained, and spectrogram analysis is simplified; and the nuclear magnetic resonance detection method can qualitatively detect the substance composition in a complex mixture, and is suitable for detecting the components of various complex mixtures.