Abstract: OBJECTIVE To analyze and identify non-target proteins in human albumin and human immunoglobulin by ultra high performance liquid chromatography tandem linear ion trap orbitrap mass spectrometry. METHODS The extract was separated on a ACQUITY UPLC peptide BEH C₁₈(300Å, 1.7 μm, 2.1 mm×100 mm) column and the gradient elution was performed with mobile phase consisting of 0.1% formic acid aqueous solution-0.1% formic acid acetonitrile. The analytes were detected in Full MS/dd-MS²(TopN). RESULTS A total of 52 non-target proteins were identified from human albumin and human immunoglobulin. Among them, 25 non-target proteins were identified in human albumin samples, and 27 non-target proteins were identified in human immunoglobulin samples. CONCLUSION The established qualitative method can rapidly, accurately and systematically identify various proteins in human albumin and human immunoglobulin. The results provide reference for the quality control of the preparation as well as its further clinical application.