The invention discloses a multi-target tracking method by means of UD factorization. The method is used for solving the technical problem of failure in radar target tracking caused by unstable numerical value structures of existing target tracking methods. The technical scheme includes that the method includes that a stable numerical value structural model is set up by means of UD factorization of estimation error variance matrixes, two positive semi-definite matrixes are subtracted in variance matrixes without estimation errors, and symmetrical matrixes with negative characteristic values cannot be generated in a processing system with limited word length. The multi-target tracking structural model is set up by means of UD factorization of estimation error variance matrixes, subtraction of two positive semi-definite matrixes in the estimation error variance matrixes is avoided, numerical diffusion in the processing system with limited word length can be avoided, and accordingly reliability of the target tracking system is guaranteed, and failure in radar target tracking and radar system errors can be avoided.