The invention discloses, which relates to the technical field of the lithium battery, discloses a method for estimating a calibration SOC error based on an OCV_SOC curve of a lithium battery. According to OCV_SOC curve data of a lithium battery, a static steady-state voltage V0 is obtained and then look-up calculation is carried out to obtain SOC data; an error analysis and estimation are carried out to obtain a calibration weight value K; and SOC calibration is carried out. According to the invention, because of unified algorithm processing on different OCV_SOC curves and voltage sampling systems, the universality and rapid adaptability of the system are improved.