Internal temperature field of solid-solution treated BT22 titanium alloy during cooling was simulated using ANSYS finite element software and the temperature isopleth map of workpieces was plotted during this procedure. Inhomogeneity of temperature distribution during cooling was analyzed from two points of view, i.e. the temperature-time curve and position-temperature curve of workpiece interior. By comparison the relative error of actual curve and simulation curve is 2%-5%. The actual cooling curve was divided into three phases: fast cooling phase, gentle cooling phase and slow cooling phase. The reason of phase formation was also analyzed.