A millimeter wave phase-locked source was designed by the principle of miniaturization and low phase noise. Some high-performance components,such as phase-locked loop, frequency divider, integrated VCO, etc. were chosen, and the millimeter wave highdensity assembly technology and SMT were utilized. The millimeter wave phase-locked source developed by the authors is characteristic of small size,low phase noise,fast locking and high reliability,and can be used in airborne and bombborne environment.