Hybrid structure noise shaping (NS) SAR ADC combines both SAR ADC and sigma–delta ADC technologies with the advantages of high precision and low power consumption. In NS SAR ADC, mismatch error shaping (MES) method is used to solve the mismatch of low-level capacitors, and Data Weighted Averaging (DWA) method is used to solve the mismatch of high-level capacitors. The single-input comparator is improved into a dual-input comparator. The buffer and integrator circuits are realized by the static op-amp. The noise of op-amp is reduced by chopper technology and the accuracy of ADC is improved. A high-precision NS-SAR ADC with a sampling frequency of 1MSps and bandwidth of 25kHz was designed using the GSMC 90nm process. When the input signal is at full scale, the ENOB of the NS SAR ADC is higher than 14.73 bits, the SFDR is higher than 98dB, the average power consumption is 567.93μW and the quality factor is 169.2dB.