Mechanical Properties and microstructures of four kinds of V-Ti binary alloys were examined before and after neutron irradiation. The neutron irradiation was done in JMTR (Japan Material Testing Reactor) at an ambient temperature up to 1.5xl0^ n/m^2 (E>0.1MeV) and in RTNS-II (Rotating Target Neutron Source-II) at room temperature up to 5x10^n/m^2 (14MeV). The tensile yield strength of unirradiated V-Ti alloys increased with Ti contents, it indicated a maximum value at near V-40Ti and slightly decreased at V-60Ti. The yield strength of high Ti contents V alloys were slightly affected by neutron irradiations. JMTR irradiation gave many effects on the tensile property, while RTNS-II irradiation affected only the elongation
