Noninvasive　or　minimally　invasive　laser　lipolysis　has　great　potential　to　reduce　obesity,　but　the　absorption　of　near　infrared　laser　by　water　may　cause　thermal　damage　of　dermis.　At　present,　there　is　no　effective　cooling　method　to　protect　normal　skin　tissue　from　thermal　injury,　which　restricts　the　development　of　laser　lipolysis.　A　novel　multipulsed　cryogen　spray　cooling　for　laser　lipolysis　was　proposed　to　protect　epidermis　and　dermis.　Numerical　simulation　based　on　multi-layer　uniform　skin　tissue　model　and　Pennes　biological　heat　transfer　equation　was　conducted　to　investigate　the　cooling　effect　of　continuous　and　multi-pulsed　R134a　cryogen　spray　cooling.　It　was　found　that　continuous　spray　cannot　meet　the　requirement　of　laser　lipolysis　both　in　temperature　and　skin　depth.　Under　the　same　accumulative　spray　time,　the　cooling　depth　of　multi-pulsed　spray　is　greater　than　that　of　continuous　spray.　The　lowest　temperature　at　1　mm　below　skin　surface　after　multi-pulsed　cryogen　spray　can　reach　to　11　with　pulse　width　of　10　ms,　interval　time　of　2500　ms,　spray　times　of　10　and　duty　cycle　of　0.004,　and　the　simulation　cooling　depth　achieves　5000　μm,　which　can　satisfy　the　cooling　depth　requirement　of　laser　lipolysis.　©　All　Right　Reserved.