The clotting assay was replaced by the chromogenic substrate assay which is recommended by the European Pharmacopoeia (EP) and the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis based on the reliability convenience and simplicity of the chromogenic assay, A correlation study was carried out with a one-stage factor Ⅷ : C clotting assay and the performance of the chromogenic assay was evaluated using two test kits that fulfilled the requirements of EP for factor Ⅷ concentrates test. Although chromogenic assay has partly differences in measurement principle and standardization, this assay has a high correlation with clotting assay in various types of factor Ⅷ concentrates and factor Ⅷ standard. We conclude that the chromogenic assay for factor Ⅷ : C concentrates correlates well with the clotting assay and shows good analytical performance.