By using advanced accuracy design concept,Nano-CMM's structure is designed,which is set-up by choosing high degree of accuracy components.The traditional Abbe error is solved due to the design of the structure of the Nano-CMM.By studying the modern accuracy ensuring theory and technique,the nanometer level's analysis of total error source of the Nano-CMM is processed.The uncertainty calculating formula is deduced.The reasonable error distributing and design are done according to the given accuracy target.The needed nanometer level calibrating instruments' technic index are put forward.The result of accuracy design meets the measuring accuracy demand of Nano-CMM is made.