Titanium alloys, characterized by their high specific strength, low density, corrosion resistance, oxidation resistance, high-temperature stability, and low neutron cross-section, are increasingly utilized as critical components in marine and space nuclear power systems. To enhance the radiation resistance of titanium alloys and advance their widespread use in nuclear engineering, considerable efforts have been made to address key issues related to the irradiation effects of titanium alloys. This paper reviews the development and irradiation effect studies of titanium and its alloys in the nuclear domain and provides a comprehensive overview of defect evolution and interaction mechanism of different advanced titanium alloys under various particle irradiations (such as neutrons and ions). Additionally, it summarizes the impact of service conditions (temperature, stress, and irradiation) on the mechanical properties of titanium alloys, including hardness, tensile strength, fatigue, and creep. Finally, based on the research status on titanium alloys for nuclear applications, the paper explores future research directions of irradiation effect and trends to improve irradiation resistance.