Abstract: The working principle of the capacitance is introduced. The accuracy of the capacitance sensor is analyzed. A new and concrete method is suggested to calculate graduated line error of capacitance sensor. The results from this suggested calculation method coincided quite well with the actually measured ones. It is concluded that in the manufacturing of the main elements (movable and fixed grid plate) of capacitance sensor, the precision need not be too high. Therefore, this method of calculation has important practical value.

Key words: Capacitance, Error, Graduated line, Sensor