［［Objective ］］ A method of two -dimensional liquid chromatograohy was established to simultaneously determine the content of lactoferrin and immunoglobulin G in dairy products.[Methods ] The pretreated samples were directly injected into the constructed system.Target protein and other effects were separated on a Pharmacia HI -Trap Protein G as the first -dimensional column using a mobile phase consisting of sodium phosphate buffer and glycocoll buffer by gradient elution lactoferrin and immunoglobulin G were separated on a BioCore SEC -300 (4.6 mm ×250 mm,5 μm) as the second -dimensional column using a mobile phase consisting of water and sodium phosphate buffer by gradient elution.[Results ] The results showed that the standard curves of Lactoferrin and Immunoglobulin G were linear with R>0.99.The quantitation limits of Lactoferrin in solid samples was 20 mg/kg while in liquid samples was 13 mg/kg,the recovery rate were 91.0%~107.0% and the RSD were 2.4%~5.3%.The quantitation limits of Immunoglobulin G in solid samples was 34 mg/kg while in liquid samples was 7 mg/kg,the recovery rate were 91.2%~104.0% and the RSD were 2.1%~4.7%.[Conclusion ] The online two -dimensional liquid chromatography system established in the experiment has the advantages of simple pretreatment,high automation,high analysis efficiency,high accuracy and good repeatability,and is suitable for the determination of lactoferrin and immunoglobulin G in dairy products.