The invention provides a remote sensing hyperspectral image band selection method based on conditional mutual information, which comprises the following steps of: A, opening a hyperspectral remote sensing image and labeling a sample to be classified by man-machine interaction; B, grouping: carrying out band grouping by utilizing the conditional mutual information among all adjacent bands under given class condition according to the sample to be classified obtained from the step A; and C, searching: carrying out search calculation on the grouped bands obtained from the step B by utilizing a search algorithm combining a support vector machine and a genetic algorithm so as to find out an optimal band combination; and on this basis, pruning by using a self-adaptation branch and bound algorithm. Through the combinational use of the band grouping based on the conditional mutual information and the pruning based on the self-adaptation branch and bound algorithm, redundancy and noise grouping which are caused by noise perturbation are avoided, the frequency of band grouping is reduced and the classification accuracy of the band combination is improved.