〔Abstract〕 In order to look for the plasma differential proteins(DEPs) and the possible plasma protein markers, we analyzed the proteomics in plasma of patients with primary chronic angle closure glaucoma. The plasma was collected, and iTRAQ and LC-MS/MS were performed to find the different proteins(DEPs). The DEPs were analyzed by GO and KEGG to find out the main pathways and key proteins. 143 statistically significant proteins were screened by mass spectrometry(P<0.05), of which 49 were up-regulated and 94 were down-regulated. The DEPs were analyzed from three parts such as the molecular function, biological process and cellular component by GO analysis. The main pathways are metabolic pathway and complement coagulation cascades,the key proteins are divided into the following three kinds according to their different functions:(1) regulating the glaucoma optic ganglion cells: HGFA;(2) oxidative stress related: glutathione peroxidase 3,SOD,Peroxiredoxin-2;(3) immune response related: C4,C4 BP. These differential proteins provide new plasma markers for clinical diagnosis. It helps us to understand the pathological mechanism of primary angle closure glaucoma and provides a new idea for clinical diagnosis.