Abstract: Marine engineering equipment serves long-term under multi-factor coupled environments featuring high salinity, high humidity, high hydrostatic pressure, as well as corrosion, fatigue, erosion and cavitation. Such service conditions raise higher requirements for lightweight design, corrosion resistance, strength-toughness, dimensional stability and long-life reliability of critical components. Titanium alloys possess advantages including low density, high specific strength, outstanding seawater corrosion resistance, favorable low-temperature toughness and non-magnetism, and thus act as vital structural materials for marine engineering equipment. As deep-sea facilities, marine power systems, seawater conveying systems and propulsion systems develop toward larger scale, integration and complication, the demands for large and complex titanium alloy castings such as pump-valve housings, impellers, propeller blades, deep-sea connectors and gas turbine casings keep growing. Centered on the main line of "marine service demand-cast titanium alloy materials-large complex castings-manufacturing equipment-quality assurance", this review summarizes the material systems, typical castings and upscaling tendency of titanium alloys applied in marine environments. It emphatically analyzes the development status and application features of key facilities, such as vacuum arc remelting, induction skull melting, vacuum induction levitation melting, vacuum consumable electrode skull melting and casting, hot isostatic pressing and vacuum heat treatment. From the aspects of composition matching, melt purification, mold filling and solidification, defect control, post-casting densification and dimensional stability, the requirements on equipment capacity and process control for manufacturing large complex titanium alloy castings are discussed. Finally, it is pointed out that the stable, controllable and industrial-scale development of domestic large complex titanium alloy castings for marine engineering shall be promoted via developing novel cast titanium alloys, constructing high-capacity high-cleanliness melting-casting equipment, implementing coordinated heat treatment control, and establishing supporting non-destructive testing and service evaluation systems.