The invention discloses a radar target blind source separation method based on an FFDIAG algorithm. According to the main thought, a F-norm-based target matrix cost function L(V) and the kth radar target matrix are calculated in sequence to be subjected to the nth iteration, then, an N*N-dimension de-aliasing matrix V(n+1), the V(n+1) is written into a cost function form L(W(n)) related to W(n), and then an absolute value of a cost function min L(Wij) containing Wij obtained after the nth iteration is calculated; if the absolute value is smaller than or equal to epsilon, an N*N-dimension matrix W(n) with the leading diagonal element being limited to be zero in the kth radar target matrix obtained after the nth iteration, the N*N-dimension de-aliasing matrix V(n+1) obtained after the kth radar target matrix is subjected to the nth iteration and a radar target matrix diagonalization structure Ck(n+1) obtained after the kth radar target matrix is subjected to the nth iteration, and the Ck(n+1) is adopted as a joint diagonalization structure of the kth radar target matrix, then, a joint diagonalization structure corresponding to K radar target matrixes is obtained, and the purpose of blind source separation in the K radar target matrixes is achieved.