The invention discloses a laser cladding method for obtaining a low-dilution-rate coat. The method comprises the following steps: carrying out laser cladding by adopting a Gaussian-distribution or approximate-Gaussian-distribution laser beam in a negative defocus mode to make the focal plane of the laser beam positioned below the surface of a workpiece; and carrying out laser cladding in the negative defocus bode by utilizing the beam cross-section energy density distribution characteristics of the Gaussian-distribution or approximate-Gaussian-distribution laser beam in a propagation path to control the negative defocus amount in the laser cladding process in a range of 4-50mm in order to obtain the laser cladding cot having an extremely low dilution rate and having a good metallurgic combination with the workpiece.