〔Abstract〕 Objective To investigate the expression and interaction of activating transcription factor 3(ATF3) and smad family member 4(Smad4) in pterygium. Methods In this study, two sets of data GSE51995 and GSE2513 in NCBI database were analyzed by bioinformatics methods to screen out the key difference-expressed gene ATF3 in pterygium when normal conjunctiva was used as the control. The differential genes identified by bioinformatics analysis were further detected by reverse transcription quantitative polymerase chain reaction(RT-qPCR). Finally, the literatures were searched and The Gene Transcription Regulation Database(GTRD) was used to predict whether there was a target gene Smad4 that might bind to the target gene. The expression of Smad4 in normal conjunctival and pterygium tissues was verified by RT-qPCR, and the interaction between the target protein ATF3 and Smad4 in the pterygium was investigated through Co-Immunoprecipitation(Co-IP). Results The results of bioinformatics analysis showed that compared with normal conjunctival tissue, there was significantly different expression of ATF3 gene in pterygium tissue(P