Objective To establish and validate an imaging capillary isoelectric focusing electrophoresis(icIEF) method for the detection of charge variants in the therapeutic monoclonal antibody SIBP-A. Methods The icIEF conditions were first optimized by adjusting urea concentration, ampholyte range, ampholyte concentration and focusing time. The optimized method was then applied to analyze the charge variants of SIBP-A, and its specificity, stability indicating property,repeatability, intermediate precision, linearity and range, accuracy, limit of quantification and stability of processed samples were verified. Results The optimized icIEF conditions included 3 mol/L urea, 1% MC gel, and a 1:1 mixture of two ampholytes (Pharmalyte 3-10 and Pharmalyte 8-10.5) as carriers, 1 kV prefocusing voltage with 1 min prefocusing time, and 3 kV focusing voltage with 6 min focusing time. In the specificity experiment, the blank group registered no significant interference peak at the sample peak while the control group exhibited normal peaks and charge variants. In the stability indicating experiment at 40 ℃ for 7 d, the sample showed normal peaks but with significant changes in charge isoforms, which were distinct from the control sample. The repeatability experiment demonstrated relative standard deviation (RSD) values of 0.48%, 0.00%, and 4.03% for the acidic, main, and basic peak relative percentage contents, respectively, and an RSD of 0.012% for the main peak's isoelectric point. Precision experiments showed RSD values of 0.89%, 0.45%, and 6.14% for the acidic, main, and basic peak relative percentage contents, respectively, with an RSD of 0.072% for the main peak's isoelectric point. In the protein range of 0.50-1.50 mg/ml, the coefficient of determination of the linear regression cure of the total peak area was 0.996 8 with good linearity, and the recovery rate of each protein concentration were 95.03%-104.35%. The limit of quantitation was 0.003 0 mg/ml.The sample of stability experiments showed RSD values of 0.56%, 0.00%, and 8.61% for the acidic, main, and basic peak relative percentage contents, respectively, with an RSD of 0.056% for the main peak's isoelectric point at 10 ℃. Under room temperature condition, the charge variants changed from 3 h. Conclusion The developed icIEF method effectively detects and characterizes charge variants and isoelectric points in the therapeutic monoclonal antibody SIBP-A. The specificity, stability indicating property, repeatability, intermediate precision, linearity and range, accuracy, limit of quantitation and stability at 10 ℃ are all satisfactory, making it suitable for release testing and stability testing of the antibody.