Today,　colloidal　quantum　dots　(CQDs)　have　received　wide　attention　due　to　their　properties　of　tunable　infrared　absorption.　For　example,　HgTe　colloidal　quantum　dots　have　shown　excellent　optical　absorption　(absorption　coefficient　alpha　＞　10(4)　cm(-1)),　spectral　absorption　tunability　covering　the　entire　infrared　atmospheric　window,　and　even　the　terahertz　(THz).　However,　the　efficient　surface　passivation　of　HgTe　CQDs　was　limited　by　the　highly　sterically　hindered　long-chain　organic　ligands.　Here,　we　demonstrate　a　new　method　to　synthesize　monodisperse　mid-infrared　HgTe　CQDs,　and　the　preparation　process　of　the　Hg　precursor　solution　is　optimized.　With　I-　in-situ　passivated　on　the　surfaces,　the　spherical　HgTe　quantum　dots　are　successfully　synthesized　with　the　tunability　size　from　8　to　15　nm.　The　noise　current　density　of　the　photoconductive　device　is　as　low　as　10(-11)　A　center　dot　Hz(-1/2)　at　130　K　with　a　frequency　of　1　Hz.