The manufacturing of complex parts can be easily achieved by additive manufacturing (AM), which has attracted a significant attention from both academia and industry. Regardless of the shape of the model, the 3-axis AM techniques slice the model into a series of sections along the Z-axis and then use a fixed direction filling algorithm to plan the interiors of the sections. This approach greatly simplifies the planning of manufacturing processes. However, this directional construction method can lead to a series of problems, such as staircase effect, supporting effect, anisotropic mechanical property, and sizing limitation. In order to address these issues, both academia and industry have investigated multi-axis AM technology. Multi-axis AM dynamically constructs parts through redundant degrees of freedom, thus overcoming the problems of 3-axis AM process. This paper analyses the limitations of 3-axis AM process, summarizes the potential of multi-axis AM technology and describes methods for implementing multi-axis AM. The paper concludes with a discussion of the new opportunities and current challenges of multi-axis AM technology.