Abstract: Continuous fiber-reinforced thermoplastic composites offer exceptional mechanical and chemical properties, attracting widespread attention in both academia and industry. To meet the automation requirements for high-performance complex structural components, additive manufacturing technologies for continuous fiber-reinforced thermoplastic composites have garnered significant interest. These manufacturing methods include Fused Deposition Modeling and automated fiber placement. The additive manufacturing process involves multi-scale physical phenomena, presenting a complex interplay that is not yet fully understood. The inherent properties of thermoplastic polymers, such as their high melting points and viscosities, further complicate processing, posing substantial challenges in the control of manufacturing processes. Addressing the intricate mechanical challenges within the manufacturing process can be facilitated through the application of multi-scale process mechanics simulations. The integration of these simulations with theoretical and empirical research aids in forging a clear correlation between manufacturing process parameters and the quality of the final product. This provides theoretical support for optimizing process parameters and equipment module design. However, the implementation of multi-scale process simulation requires in-depth comprehension and precise description of physical phenomena. It also involves the design of sophisticated algorithms and the construction of intricate models, thereby increasing the difficulty and challenge of the simulation. This paper reviews recent studies employing various numerical modeling approaches to investigate the processing mechanisms of continuous fiber reinforced thermoplastic composites during the AFP and FDM processes. It also outlines potential promising directions in the field.