Ammonia concentration is the major parameter to evaluate livestock breeding farms atmosphere quality and it also is regarded as the key indicator to describe the production of livestock breeding farms. Based on the oxidation characteristics of ammonia, this paper presented a new intelligent detecting instrument, the intelligent ammonia sensor, for the measurement of ammonia concentration, which used the microcontroller STM8L152 as the key control module. However, the TEDS module, which is useful to self-identification, self-diagnosis and self-calibration of ammonia sensor, is in the flash of the STM8L152 and only if the STM8L152 conveys the warning signal to the alarm module, will the alarm module starts the worker loop.