[Objective] To introduce a modified method for immunoblotting in detecting protein and to show all the details needing to be paid attention to. We take COX-2 for example. [Method] Total proteins were extracted and quantified. Denatured proteins were separated by SDS-PAGE and were transferred semi-dryly to NC membrane, then the latter was bound with specific antibody. Finally, protein expression was detected by ECL.[Result] The method was concise and easy to manipulate. The method had been successfully used to detect COX-2 protein in our lab and the pictures were reproducible. [Conclusion] Every step of the method is described in detail. It is helpful for novice to carry out immunoblotting. This established method is worthy to be recommended.