The work aims to analyze effects of laser shock peening (LSP) on tensile properties at room and high temperature of titanium alloy. Plate-shaped TC17 titanium alloy tensile samples were dual-side laser shocked once by a YAG ns-pulse laser, with pulse energy of 25 J, pulse width of 15 ns, spot size of 4.2 mm×4.2 mm and overlapping rate of 10%. Tensile tests were performed at room temperature and 400 ℃ to obtain yield strength, tensile strength and elongation at break of the samples before and after LSP. Residual stress on sample surface was tested in X-ray diffraction method, and fracture microstructure of the tensile samples was observed with SEM. In the tensile test at room temperature, tensile strength at room temperature and elongation of TC17 titanium alloy were almost not affected by laser shock peening, but yield strength at room temperature decreased by nearly 6.1% after LSP, and there was no obvious yield point on the samples receiving LSP or not, and surface residual compressive stress 10 mm from sample failure position decreased by nearly 12% than that before stretching. In the tensile test at 400 ℃, tensile strength at high temperature and yield strength of the TC17 titanium alloy were slightly affected by laser shock peening, there were obvious yield points on the samples receiving LSP or not, and surface residual compressive stress 10 mm from sample failure position decreased by nearly 44% than that before stretching. Yield strength is affected to a certain extent as significant residual compressive stress is induced by LSP on TC17 titanium alloy. Yield strength of the peened samples closely relates to relaxation rate of residual compressive stress during stretching. The relaxation of residual stress during stretching at room temperature is slower than that during stretching at 400 ℃. As a result, balance tensile stress zones inside the samples are more likely to yield, which explains slight yield strength decrease at room temperature.