The invention belongs to the technical field of processing of spectral data and soil monitoring and discloses a detection method capable of judging precision and used for analyzing the content of soil nutrients based on spectral characteristic wavelength. The detection method comprises the following steps: adding a soil sample spectrum, adding a nutrient content value of a soil sample, carrying out spectral pre-treatment, extracting the spectral characteristic wavelength, carrying out multivariate calibration, carrying out precision judgment and the like, so as to finish modeling and finish predication preparation work; and finally, outputting a predicated value. The detection method has no artificial interference and can be used for simply, rapidly and effectively realizing spectral unmixing of the soil nutrients; and the detection method can be used for unmixing a plurality of spectral types and realizing the spectral unmixing of the plurality of soil nutrients.