With the development of science and technology, high-performance liquid chromatography is widely used in pesticide analysis, especially the popularization of ultraviolet variable wavelength detectors, which has greatly improved pesticide analysis technology. This article studies the selection of the maximum and suitable wavelengths for many compounds. First, it can solve the problem of overload of ultraviolet light wave absorption for compounds weighing more than 50 mg. When analyzing pesticides, the quality of weighed samples is generally the most effective.