The present invention provides a method for distinguishing nonlinear subspace of one-dimensional distance image which belongs to field of radar target recognition. Target one-dimensional distance image is transferred nonlinearly and mapped to high-dimensional characteristic space, nonlinear regular sub-image characteristics of each kind of target is obtained by characteristic transform matrix of high-dimensional characteristic space to form nonlinear sub-image space of each kinds of target, when the radar one-dimensional distance image of target is input, the sort of one-dimensional distance image is determined according to Euclidean distance between nonlinear regular sub-image and nonlinear sub-image space. Step: radar one-dimensional distance image training vector of target is determined; between-class scatter matrix sB after nonlinear transform and kernel function are determined; nonzero eigenvalue of C and corresponding eigenvector are determined; kind-in scatter matrix Q is determined; nonzero eigenvalue of Q and corresponding eigenvector are determined; all training one-dimensional distance image nonlinear regular sub-image of each kind target are determined; nonlinear sub-image space of each kind of target is determined; input one-dimensional distance image nonlinear regular sub-image of target is dertermined; Euclidean distance between nonlinear regular sub-image and nonlinear sub-image space is determined; sort number of input target one-dimensional distance image is determined.