A single-axis capacitive accelerometer chip with AC offset voltage cancellation function is proposed, and it consists of the front-end MEMS acceleration sensor and the back-end CMOS signal processing circuits. In fact, an ac offset suppression loop is proposed to cancel the ac offset voltage originated from the initial capacitance mismatches of the MEMS acceleration sensor. The proposed chip was fabricated by using TSMC 0.35μm 2P4M mixed-signal standard CMOS process and MEMS post process. Including pads, the chip area is 2.43×2.07 mm2, and the measured sensitivity is 120.4 mVpp/g within the ±9g sensing range.