One-dimensional S=1 XXZ chains with uniaxial single-ion-type anisotropy are studied by numerical exactdiagonalization of nite-size systems. The numerical data are analyzed using conformal eld theory, the level spectroscopy, phenomenological renormalization-group, and nite-size scaling method. We thus present a quantitatively reliable ground-state phase diagram of this model. The ground states of this model contain the Haldane phase, large-Dphase, Ne el phase, twoXYphases, and the ferromagnetic phase. There are fourdifferent types of transitions between these phases: the Brezinskii-Kosterlitz-Thouless-type transitions, the Gaussian-type transitions, the Ising-type transitions, and the rst-order transitions. The locations of these critical lines are accurately determined.