本文提出了一种双SMO算法。该算法在原数据集的抽样数据集上使用SMO算法得到近似分类超平面，根据近似分类超平面得到原数据集的所有支持向量，再次使用SMO算法得到最终的分类超平面。-In this paper,double SMO which is a improved SVM training algorithm is presented.This algorithm finds a approximate separating hyperplane on the sample data set by SMO algorithm,according to the approximate separating hyperplane,support vectors are collected,the separating hyperplane is achieved by SMO aogorithm again.