Abstract: We establish the scalar curvature and distance bounds for general finite time solutions of the Kahler-Ricci flow, extending Perelman's work on the Fano Kahler-Ricci flow. We further prove that the Type I blow-ups of the finite time solution always sub-converge in Gromov-Hausdorff sense to an ancient solution on a family of analytic normal varieties with suitable choices of base points. As a consequence, the Type I diameter bound is proved for almost every fibre of collapsing solutions of the Kahler-Ricci flow on a Fano fibre bundle. We also apply our estimates to show that every solution of the Kahler-Ricci flow with Calabi symmetry must develop Type I singularities, including both cases of high codimensional contractions and fibre collapsing.