Through　the　finite　element　software　abaqus,　the　finite　element　model　of　prefabricated　segmental　box　girder　with　one　joint　and　three　spans(42m+66m+　42m)in　the　section　from　the　airport　expressway　to　XinZheng　is　established.　It　is　demonstrated　that　the　stress　of　the　box　girder　and　the　stress　between　joints　are　in　the　safe　range　during　the　symmetrical　splicing　construction　of　middle　piers.　By　changing　the　value　of　the　pre-stress,　the　influence　of　pre-stress　on　the　mechanical　performance　of　the　box　girder　in　the　construction　stage　is　discussed.As　a　result,　during　the　construction　process,　the　roof　pre-stress　has　a　bigger　impact　on　the　construction　stage　than　the　web　pre-stress,　and　it　is　proposed　that　the　loss　of　pre-stress　should　be　reduced　during　the　construction　stage.　©　2021　Institute　of　Physics　Publishing.　All　rights　reserved.