Capacitor mismatching is a main source of error for switched-capacitor analog-to-digital converter.A differential capacitor pairing technique is presented to reduce capacitor mismatch error. By comparing the capacitance of capacitors and then accordingly exchanging the position of capacitors, the gain error of the stage, which is proportional to the relative error between the sum of differential sampling capacitors and the sum of differential feedback capacitors,is obviously reduced. Probability analysis and Monte Carlo simulation indicate that the linearity of the analog-to-digital converter can be improved by 0.6 bit. Compared with other capacitor mismatch calibration techniques,the proposed technique has characteristics such as simple calibration circuits, unweakened conversion speed, and insensitive to the operation environment.