Compression tests were carried out to investigate the hot-deformation behavior of Ti-6Al-4V alloy in the temperature range of $915^{circ}C$ to $1015^{circ}C$ and the strain rate range of $10^{-3}s^{-i}$ to $10s^{-1}$. Under the given test conditions, the hot-deformation of Ti-6Al-4V alloy was mainly led by dynamic recovery rather than by dynamic recrystallization. The activation energy for the plastic deformation in $alpha+eta$ field was about 894 kJ/mol and $eta$ field was 332kJ/mo1. Processing map for hot working are developed on the basis of the variations of efficiency of power dissipation($eta$=2m/m＋1) and flow instability criterion using the dynamic material model. The optimum process condition in the ($alpha＋eta$) field was obtained at the temperature ranges of $930^{circ}C$ to $955^{circ}C$$^{circ}C$ and a strain rate of $10^{-3}s{-1}$.