Infrared　thermography　thermometer　is　a　non-contact　temperature　measuring　equipment,　which　is　widely　used　in　the　stage　of　large-scale　epidemic　of　the　covid-19　pandemic.　It　is　used　for　rapid　screening　of　human　body　temperature　in　crowded　places　at　the　entrance　and　exit　of　airports,　docks,　shopping　malls,　stations　and　schools.　But　when　the　outdoor　temperature　approaches　or　exceeds　the　body　temperature　in　summer,　can　this　method　of　measuring　body　surface　temperature　by　infrared　thermal　imager　be　used　as　a　standard　for　screening　fever?　Under　the　condition　of　high　temperature　in　summer,　the　field　experiment　of　measuring　body　temperature　by　infrared　thermal　imager　is　carried　out,　the　experimental　results　are　analyzed.　We　recommend　the　use　of　relative　temperature　difference　for　screening　patients　with　fever.　©　2021　Institute　of　Physics　Publishing.　All　rights　reserved.