The invention discloses a method for nondestructively measuring main fatty acid content of peanut seeds. The method comprises the following steps of: based on the Fourier transform near-infrared diffuse reflection spectrum technology, scanning spectrums by adopting a best integrating sphere diffuse reflection mode for eliminating solid granule non-uniformity, establishing a multiple regression mathematical model by using full peanut seeds of multiple genotypes as standard sample sets, and predicting the main fatty acid content of an unknown sample through the model. The method is nondestructive, does not need to treat the sample, and does not harm the vitality and tissue structure of the seeds. The method has the advantages of simple operation, high sensitivity, high scanning speed, good signal-to-noise ratio and high measurement speed, and is suitable for high oleic acid quality breeding, germ plasm resource identification and inheritance rule research of peanuts.