This design pays much attention on analyzing and calculating Miller capacitor in operational amplifier to optimist OP (Operational Amplifier). The design for a 8-bit high speed, low power pipeline ADC is based on standard 0.18um CMOS technology, with 3.3 power supply. The results show that the dc gain of the operational amplifier is 96dB, the gain-bandwidth is 167MHZ, and the ADC can achieve 8bits resolution and 10M samples/s.