Oscillating water column (OWC) is the most widely used wave energy converting technology for onshore structures. The interest in OWC wave energy converters (WECs) has been rising in the last decade because of its capability of long-term operation with high reliability and survivability. The impulse and Wells turbines, acting as axial-flow self-rectifying turbines and rotating unidirectionally in reciprocating airflows generated by the air chamber, play a key role in the pneumatic power conversion of OWC facilities. Although these turbines were developed based on theoretical analysis and steady-state laboratory tests, computational fluid dynamics (CFD) technologies have become a popular and convenient desktop tool for their design and optimization. This review aims to bridge the knowledge gap between engineering applications and CFD achievements for this type of turbine. Recent developments in the CFD modeling, geometry optimization, and performance enhancement have been summarized. Perspectives on the CFD model for OWC axial-flow turbines and its future trends are also proposed.