Abstract: A dual microstructure/dual property distribution is required for the titanium alloy compressor disk: basketweave microstructure in the blade region and equiaxed microstructure in the hub region. For this purpose, hot compression tests were conducted on TC18 titanium alloy with basketweave microstructure using a Gleeble-3500 thermal simulator. The deformation temperature was set at 780~860 ℃, and the strain rate was 0.001~0.1 s⁻¹. The effect of deformation parameters on the spheroidization of lamellar α phases was probed and a spheroidization kinetics model was established. Results indicate that raising deformation temperature and strain or lowering the strain rate, can increase volume fraction of spheroidized lamellar α phases. The dynamic spheroidization kinetic curves of lamellar α phases present a typical characteristic of S-shape and follow the Avrami equation. The proposed kinetic model for dynamic spheroidization achieves high prediction accuracy, with a correlation coefficient of 0.9295. It can reliably predict the volume fraction of spheroidized phases during hot deformation.