This work aimed to evaluate the combined effect of stress triaxiality and strain rate on the tensile behavior of the titanium alloy. The results of experimental studies and numerical modelling of the mechanical behavior of alpha titanium alloys were received and summarized. This paper presents the results of the research of mechanical behavior of titanium alloy VT 5-1 (this is an analog of Ti-5Al-2,25Sn) in a wide range of strain rates (from 0.001 to 1000 1/s) and stress triaxiality (0.0 - 0.6). Specimens of four different shapes were used in experiments to study the deformation and fracture under uniaxial tension, shear. Experimental studies were performed on servo-hydraulic test machine Instron VHS 40/50-20. The model of inelastic deformation and ductile damage criterion were proposed to describe the ductility of the titanium alloy in a wide range of strain rates and stress triaxiality.