The concept of atmospheric retrievable index (ARI) is introduced to provide the criterion for channel selection. The definition of ARI is given by 1min the ratio of the determinant of the covariance matrix of the error of the results and the covariance matrix of the error of the background, and the value is within the interval between 0 and 1. For all the probable subsets, the one giving the greatest ARI is the subset to be selected. To illustrate the implementation and effect iveness of the method, two series of channel selection experiments of IASI for retrieval atmospheric temperature and humidity profiles using physical retrieval method are carried out. The results of the experiments show that the method can provide an effective approach to the channel selection for the application of high spectral resolution data.