Hot deformation behavior of TB8 alloy near the β-transus was investigated via hot compression tests in the temperature range of 650~900 oC and at strain rates ranging from 0.01 s-1 to 10 s-1. The flow stress curves obtained in the dual phase α+β and single phase β regions were analyzed in terms of the different dependence on the flow stresses responding to different temperatures, strain rates and different microstructural evolutions. At the high strain rate of 10 s-1，the true-stress ture-strain curves have two peaks at temperature of 850 °C and 900 °C. This is a new phenomenon, which has not been reported before. The value of apparent activation energy is 233.0151 kJ/mol for dual phase microstructure and 197.8987 kJ/mol for single phase β microstructure. Furthermore, the corresponding flow stress constitutive equation of TB8 alloy in dual-phase and in single-phase regions is established.