Laser additive manufacturing （LAM） involves a complex heat-processed process, and the produced multilayer parts also have complex microstructure characteristics. The microstructure characteristics of the parts determine their mechanical properties, thus the optimization of microstructure characteristics is the key to further realize the precise control of the mechanical properties. This article reviews the microstructure characteristics of the LAM multilayer parts and summarizes the factors influencing the evolution of the microstructure characteristics, which provides a reference for the optimization of the microstructure characteristics of the LAM multilayer parts.