·AIM:To investigate the effects of high glucose condition on the proliferation and reactive oxygen species(ROS)expression in cultured human retinal pigment epithelial(RPE)cells in vitro.·METHODS:Human RPE cells were cultured in vitro and divided into four groups:control group with DMEM/F12 culture solution including 5.6mmol/L glucose;high glucose group with DMEM/F12 culture solution including 30mmol/L glucose;high glucose plus SB203580 group with DMEM/F12 culture solution including 30mmol/L glucose plus 10μmol/L SB203580 the specific in hibitor of p38 mitogen activated protein kinase(p38-MAPK);mannitol group with DMEM/F12 culture solution including 5.6mmol/L glucose and 24.4mmol/L mannitol.Cell viability was assessed by the MTT assay.ROS change in RPE cells in response to high glucose was detected with flow cytometry.·RESULTS:Compared to controls,the treatment of RPE cells with 30mmol/L glucose caused an obviously decrease of cellar viability.After pretreated with SB203580,cell viability was elevated compared with high glucose group.The ROS increased in high glucose group.·CONCLUSION:High glucose could damage RPE cells.The mechanisms may be that high glucose could evoke ROS expression via p38-MAPK pathway.·