This paper presents a scheme of W-band coherent Doppler velocity radar front-end, which can be used to measure the velocity of target ranging from 10m/s to 2000m/s. After the comparison of the advantage and disadvantage of several schemes, the scheme using the phase-locked dielectric resonator oscillator (PLDRO) and direct digital synthesis (DDS) is chosen. The two coherent X-band signals are produced by mixer and power-divider mechanism of the PLDRO and DDS. Then, transmitting signal and receiver LO is obtained by the 8th-order multiplier from the two X-band signals. The superheterodyne receiver is adopted to increase the system signal-to-noise ratio (SNR). The finished key components have good performance, indicating that the scheme increases the sensitivity and the resolution of the radar.