Hyperthermia　is　an　important　means　of　cancer　treatment　which　is　called　＇tumor　green　therapy＇.　The　clinical　heat　therapy　heating　sources　include　ultrasound,　microwave,　alternating　magnetic　field,　infrared　laser.　However,　it　is　still　difficult　to　accurately　measure　the　temperature　of　tumor　hyperthermia　and　the　dose　of　hyperthermia.　Here,　NaYF4:Er3+　nanoparticles　were　injected　into　a　small　part　of　isolated　pig　liver,　and　heated　it　with　1550nm　infrared　laser.　At　the　same　time,　the　laser　excited　the　NaYF4:Er3+　nanoparticles　to　generate　up-conversion　green　fluorescence.　The　fluorescence　intensity　ratio　was　used　to　measure　the　temperature　of　the　heating　part　in　real　time.　©　2021　Institute　of　Physics　Publishing.　All　rights　reserved.