In order to meet the fast on-site calibration of temperature sensor and temperature measuring instruments, A kind of intellectualized high-precision temperature calibration device based on Embedding System is developed. This device based on ARM and a proportional-fuzzy self-tuning PID optimal control algorithm is characterized by high accuracy and fast response. Its performance parameter is given as following: measuring range, 35oC-600 oC, accuracy, ± 0.50 oC (at 600 oC), resolution ,0.01 oC, stability time 40 minutes(at 600 oC). To ensure the portability of μC/OS-II, a set of data types is defined by authors. As same as all the real time cores, it is necessary for μC/OS-II to reject the interrupt before accessing the critical section of codes, and the interrupt is to be allowed again after the access. In this paper, the design of system , especially the porting of μC/OS-II operating system, is introduced.