In this work, we introduce a new method using non-equilibrium atmospheric pressure plasma jet (N-APPJ) for the synthesis of semiconductor quantum dots in liquid media with low power consumption at room temperature. In this method, the solution containing CdSO4, Na2S2O3 and thioglycolic acid (TGA) was treated by N-APPJ. Firstly, the key role of plasma applied voltage on the power consumption and the produced plasma reactive species was considered. We then continue to demonstrate that the optical properties such as absorption and photoluminescence of cadmium sulfide quantum dots (QDs) can carefully be controlled with the plasma parameters. Here, the effects of two major plasma parameters such as the plasma applied voltage and treatment time on the size of CdS QDs were investigated. The size of nanoparticles increases with the increase of the voltage and treatment time. It was also displayed that the change of the concentration of Na2S2O3 and TGA in the solution had no significant effect on the size of QDs in plasma method. Finally, X-ray diffraction, X-ray fluorescence spectrometry and transmission electron microscopy were employed to determine the composition, size and crystallinity of prepared CdS QDs.