A high precision and low noise operational amplifier was designed and implemented. A base current elimination technique was proposed to compensate the base current of the input transistor pairs, which reduced the input bias current of the operational amplifier effectively. So the input noise voltage was reduced by increasing the collector current of the input transistors, achieving a lower total equivalent input noise of the operational amplifier. At the same time, the collector-emitter voltage compensation circuit was used to eliminate the influence of the Early effect and improve the circuit accuracy. The chip was designed and fabricated in a 36 V complementary bipolar process. The measurement results show that the offset voltage of the chip is 6.94 μV, the voltage noise density at 1 kHz is 5.6 nV/Hz, and the current noise density is 0.9 pA/Hz.