Affinity-mediated protein separation is an integral part of proteomics,the most outstanding of which is immunoproteomics.However,in the immunoprecipitate system overwhelming Ab and Ag conceal Ag interacting proteins as the research targets,which is the rate-limiting step in the progress of comparative proteomic analyses.We presented a convenient and accurate method to tackle this problem.1 mol/L NaCl elution buffer was applied to the complex Rubisco immunoprecipitate of Arabidopsis,the weakest force involved in the system was selectively broken up,resulting in the enrichment of Rubisco interacting proteins accessible for further comparative protein gel profile.The easy-to-use method sheds light on a narrow-down strategy supplement for comparative immunoproteomics.