Metal additive manufacturing (MAM) technology has been developed rapidly in aerospace, ship building,automobile manufacturing and bio-medical industries. However, MAM technology is characterised by a number of issues that are slowing its wider implementation. The peculiar microstructure of MAM components leads to anisotropy, the components are affected by residual stresses and distortion during MAM, and also it is easy to produce cracks and holes. Therefore, this paper mainly introduces several methods and techniques for improving the microstructure and performance of metal additively manufactured materials, such as optimization of process parameters, post-treatment, particles introduction,ultrasonic interference technique, ultrasonic impact treatment, rolling and ultrasonic micro-forging technique.