This　paper　proposes　a　novel　method　for　junction　temperature　measurement　of　power　metal-oxide-semiconductor　field-effect　transistors　(MOSFETs).　The　measurement　method　is　using　the　turn-ON　delay　of　impulse　signal,　which　is　the　delay　time　between　the　rising　edge　of　impulse　signal　and　the　corresponding　rising　edge　of　drain-source　current.　Results　show　that　the　turn-ON　delay　has　a　good　linear　relationship　with　temperature,　and　the　method　is　suitably　efficient　for　accurate　junction　temperature　measurement　of　power　MOSFETs.　The　proposed　method　is　verified　using　the　thermal　infrared　method.　Finally,　this　method　is　used　to　measure　the　real-time　junction　temperature　of　power　MOSFET　device　in　a　dc-dc　boost　converter.