Comparator based switched capacitor technique is a new topic because of its suitability of scaling and its inherent low power consumption. Since CBSC technique suffers from the overshoot due to the comparator delay, this paper gives a detailed analysis on the overshoot signal, and a common mode feedforward circuit is proposed to correct the overshoot error. A 10-bit 100MS/s pseudo differential pipelined ADC is presented to verify the idea. The SNDR of the pipelined ADC is 55dB.