A measurement approach for high-precision and low cost capacitive pressure sensor is presented.A RC oscillate circuit is used to modulate capacitive variance to frequency signal

which is measured by SSP1492.A C8051F021 MCU is employed to process the compute task from frequency variance to pressure variance by high-order polynomial so that high-precision pressure measurement is achieved.Experimental results show that the measurement precision by the proposed method can achieve 0.02 %FS.