The method of Maximum Entropy Spectrum Estimation is used to extrapolate four airplane data, and ISAR imaging is done on the basis of it. The four characters of ISAR images, i.e. geometric moment, invariants based on geometric moment, shape and quantized energy belt are adopted in the study of the arithmetic theory of linearity and non-linearity about SVM, and a method of target recognition and classification based on SVM is proposed. The M-ary method for multi-target classification is used to classify the airplanes, and 40 different data fields of each target are chosen for imaging. Compared with the usual BP and RBF neural network algorithms, this method is good in recognition, and its discrimination can reach 97%.