In this research, the combination of resonance and vibration of ultrasound created by ultrasonic atomizer 1.63 MHz was employed to disperse silver nanopowder (4-40 nm in diameter) in water without any additional chemical phases, which has been considered very difficult. To evidence the dispersive function of a proposed technique, it was compared to other two well-known conventional mechanical ultrasonic dispersing techniques, viz., ultrasonic cavitation (at 20 kHz) and sonication bath (at 19 kHz). Dynamic light scattering and transmission electron microscope were utilized to analyze the distribution behavior of silver nanoparticles in colloids after being dispersed. The comparison indicated that the proposed technique dispersed silver nanopowder in water much more homogeneously than the other two conventional techniques, with the average size of dispersed particles of a round 202 nm. In particular, small silver nanoparticles in the size of around 7 nm were almost dispersed separately one by one, a report that has not been reached by conventional ultrasonic cavitation dispersing technique or sonication dispersing technique either. Moreover the colloid dispersed by the proposed technique was stable with its zeta potential factor of approximately 30 mV at pH=7.5.