The dilatometry behavior and microstructure of the α+β→β phase transformation in the Ti6Al4V-0.55Fe alloy were investigated during continuous heating process. Four heating rates (1, 5, 10, 15 K/min) are been applied for the dilatometry behavior research. For the α+β→β phase transformation curve, the S-shaped pattern under the different heating rates indicates that the α+β→β phase transformation is a nucleation-growth-controlled process. The mean phase transition activation energy E was obtained by the Kissinger-Akahira-Sunose (KAS) method equals to 200 kJ/mol. By calculating the corresponding Avrami index n with the increase of the β phase volume under the Kolmogorov-Johnson-Mehl-Avrami (KJMA) model, we can divide the Avrami index n into three stages which including the initial phase transformation stage (0