The main structure defects of laser cladding coatings were introduced, including enormously diluted, shape distortion, the poor adhesive strength between coating layers, stomas and micro-cracks in the coatings. Emphasized on the analysis of the reasons for various defects from the facet of crystallography, and the relevant methods to reduce defects were put forward. This prevents the defects of laser cladding coatings for us point to clear direction.