The seismic site characteristics and shear-velocity structure of the Hanoi region were analyzed by the microtremor measurements, including microtremor survey of dense single point and array measurements. Firstly, 75 single measuring stations and four arrays were conducted in the Hanoi region for the preliminary survey. Horizontal-to-Vertical Spectral Ratio (HVSR) in the Hanoi region show dominant frequencies between 0.8 and 2.0 Hz with high amplifications. Furthermore, the dispersion curve inversions of four array sites and the simulations of the microtremor HVSRs reproduce the near-surface shear-wave velocity structure, especially for the main interface, of Hanoi. It indicates that the seismic site amplification is high and dominated mostly by the soft near-surface deposits in Hanoi. The soft deposits under the Hanoi region may result in earthquake damage because of the amplification of ground motion. Therefore, the other 242 microtremor single-station measurements were conducted and analyzed to accomplish the seismic microzonation and VS30 map as the important factors of seismic design and seismic risk assessments in Hanoi.