Abstract: The traditional modification scheme is to trim the system by changing the feedback coefficient of the resistance feedback network. However, the method, arranged for the feedback resistance trimming at a specific output voltage, can not ensure the precision of different output voltage configurations. To solve the problem, analyzing the working characteristics of the loop and starting at fixed operating point of the error amplifier, a design method of high-precision Buck-boost converter was proposed based on dynamic adjusting of the current of the error amplifier. Based on 0.18 μm BCD process, the circuit design and physical implementation were carried out to verify the proposed method. The results show that the output voltage error can be reduced from ±40 mV to ±1.83 mV, and the output voltage accuracy can reach 0.0457%. When the output voltage error is less than or equal to 5 mV, the maximum error is 62.83 mV. Compared with the traditional structure, the precision of the modified voltage is less affected by the change of PVT, which greatly improves the output accuracy of the system. The method has been successfully applied in a Buck-Boost converter.