The pollutants in automobile exhaust gases mainly are CO

HC

NO

x

SO

x

and some particulates.The exhaust gases seriously pollute our living environment.NO

x

sensor for monitoring car exhaust gases is studied for monitoring the content of NO

x

exhausts gases from automobiles in order to satisfy the requirements of monitoring atmosphere and protecting environment.NO

x

sensors can be divided into three types:semiconductor

potentiometric and amperometric gas sensor.Working mechanism

construction and application of the three kinds of sensors are introducted.Development trend of miniaturization

multifunction and integration and intelligence of the automotive sensor is also predicted.