In order to quickly detect rice moisture content, a uniplanar capacitor probe was designed. A corresponding converting circuit was also designed for getting digital value of capacitance. The rice moisture content was converted into capacitance and digital value in turn by the capacitor probe and converting circuit. Finally, the rice moisture content was obtained by using single chip. After the calibration experiments and temperature characteristics experiments, the results showed that prediction error of moisture content was within ±0.8% at the range of rice moisture content of 8%~23%. With the temperature of 12~33℃ and rice moisture content of 12.86%, the temperature shift value was 0.2%/℃.