TG/DSC tests of non-hydrogenated and hydrogenated Ti-6Al-4V alloys were carried out in order to investigate the dehydrogenation behavior of hydrogenated titanium alloys. Results indicate that mass losses of the hydrogenated Ti-6Al-4V alloys are significantly different with that of the non-hydrogenated Ti-6Al-4V alloy when the heating temperature is higher than 600 oC. Mass loss of the hydrogenated Ti-6Al-4V alloy increases with the increasing of hydrogen content when the heating temperature is in the range of 600 oC to 900 oC due to the decomposition of metastable phases. The maximum mass loss of the hydrogenated Ti-6Al-4V alloy is in correspondence with its hydrogen content upon no consideration of oxidation. The optimal dehydrogenation temperature among hydrogenated Ti-6Al-4V alloys is 750 oC. The dehydrogenation process for all hydrogenated Ti-6Al-4V alloys is the same