The invention relates to a color-spun yarn color matching method based on a least square support vector machine. The method is characterized by comprising the following steps that reference color fibers are determined, and the corresponding color data value is acquired; a part of or all reference color fibers are selected, combined in different ways and mixed in different mixing ratios for spinning and sample preparation, and the reflectance values of all samples are measured; the reflectance value of a standard sample and the corresponding proportional relation serve as training samples, and an LS-SVM function model is trained; a corresponding sample recipe C is calculated; according to the prediction recipe C, sample making is conducted, a simulated sample is obtained, and the reflectance value of simulated sample is measured; through the comparison, the chromatic aberration between a target sample and the simulated sample is obtained, if the chromatic aberration meets a preset value, the proportion is determined as an optimum recipe, otherwise, recipe modification is conducted; the optimum recipe is input in an LS-SVM training set for training. The types of the reference color fibers adopted by the method are less, after the recipe obtained by calculation is verified and modified, the accuracy of the optimum recipe is high, color matching is simple and reliable, and the efficiency and the practicability are high.