This paper describes an innovative system to produce nanoparticles based on the theory of gas condensation in producing nanoparticles. In a vaccuum environment, the system used the energy produced by high frequency induction to vaporize a pure zinc rod inside the crucible. During the vaporization the chamber was filled with He gas, so the high-temperatured vaporized metal can undergo momentum exchange with He gas and at the same time, induce the vaporized metal to move to the cold trap. Upon reaching the wall of the cold condenser, the vaporized metal instantly condensed, forming nanoparticles. The TEM image shows that their average diameter was 30 nm, and the size was very consistent. In addition, the Zeta potential and average diameter of the ZnO nanofluid was also measured under different pH conditions to determine the stability of the ZnO nanofluid. Moreover, in order to verify the practicability of the fabricated ZnO nanoparticles, the ZnO nanofluid was inspected by UV/Vis absorption spectrum, and the results show that ZnO nanoparticles absorption ability was within a wavelength range from 350nm to 550nm.