As a typical kind of narrow-gap semiconductor material, Ag₂Se quantum dots has advantages of simple preparation procedure, super-low toxicity, favorable chemical stability and good biocompatibility, which make Ag₂Se QDs has a broad research and application space in fluorescent probe, biological/chemical detection and infrared optoelectronic devices. Unfortunately, synthesis of Ag₂Se QDs with high qualities faces great challenges, the super chemical affinity between silver and selenium makes QDs grow at a very fast rate, which can not be well-controlled. As a result, the synthesized QDs has a poor monodispersity and many surface defects. Especially it is hard to obtain NIR region II Ag₂Se QDs with both favorable absorption and emission properties. This paper focuses on solving the above problems. Based on the previous studies, this paper studies on the ligand of the silver precursors, the temperature and the duration of the reaction, mainly using hot-injection synthesis method. We obtained Ag₂Se QDs with strong photostability, both good NIR absorption and emission properties, their absorption and emission spectra can be modulated in the range of 1000-1600nm and 1400-1600nm, respectively. We also tried shell coating of Ag₂Se QDs, in order to improve the fluorescence emission properties.