Long-term safety and efficacy of biosimilars are approved by using abbreviated methods and clinical studies may not always adequate to ensure comparability of biosimilar mAbs comparing to its reference product. Therefore, the analytical strategy of the physicochemical comparison of a biosimilar to its reference product becomes an important data to indicate clinical similarity in safety and efficacy. FDA recommended that demonstration of biosimilarity between reference and biosimilar versions is based upon data derived from analytical studies to show "high similarity" to the reference product not withstanding minor differences in clinically inactive components. Therefore, the physicochemical analytical comparison between biosimilar and its reference product is the primary consideration during biosimilar development. In these review, the approach for physicochemical characterization, biological activity and impurities assessment were reviewed.