In order to help the readers with understanding the similarities and differences between ISO/IEC 17025:1999 and Guide 25 and thereby carry forward the implement of ISO/IEC 17025,the oringin of ISO/IEC 17025,its relationship with ISO 9001 and ISO 9002,the composition,frame and analysis of ISO/IEC 17025 and its contrast and comparision with Guide 25 are mainly described in this paper.