This paper focuses on the after synthesis of CdTe quantum dots(QDs) in aqueous solution. CdTe nanoparticles were prepared in aqueous solution using mercaptocarboxylic acid or thioglycolic acid(TGA) as stabilizing agents. QDs emit light smaller than the nano size. The contents of the mercaptocarboxylic acid, and a kind of raw material, were revealed for a period of time. We succeeded in synthesizing a very high quality QDs solution; we discussed how to make QDs better and to keep them stabilized. TGA is known as one of the best stabilizing agents. Many papers have mentioned that TGA is a good stabilizing agent. We dramatically confirmed the state of QDs after the experiments. The QDs solution can be influenced by several factors. Different content of TGA can influence the stability of the CdTe solution. Most papers deal with the synthesis of CdTe, so we decided to discuss the after synthesis process for the stability of the CdTe solution.