In present technological modern age. All the manufacturers adopt that process which governs to higher productivity that has been achieved by the various treatment of tool steel. These conventional processes improve no of characteristics to fulfill desired purpose. But all these process does not provided fully satisfaction from conventional heat treatment process. Thus a new process is being additionally employed for improving mechanical properties called cryogenic treatment process or sub-zero treatment of tool steels. During this process tool steel is proceed below Atmospheric tem. That is in minus about (-1960 C or 3100 F). Due to cooling, steel alter their mechanical properties like wear resistance, Hardness, toughness, fatigue life micro-structure alteration etc. Cryotreatment not only improve its mechanical properties but also improve thermal properties, electrical properties & easier machining etc. in this paper cryogenic treatment of tool steel AISI-D6 is perform and study is made for wear-resistance, Hardness, toughness, with respect to untreated test specimen of same, we have got improved wear-resistance capacity improve hardness as well as toughness.