Introducing　phase　transition　materials　to　random　systems　provides　a　promising　route　to　create　new　optoelectronic　functionalities　of　random　lasers.　Here,　a　phase　transition　random　laser　with　switchable　lasing　modes　is　reported,　which　is　designed　with　a　thermoresponsive　hydrogel　as　scattering　medium.　By　manipulating　the　phase　transition　in　hydrogel,　random　lasing　modes　can　be　switched　reversibility　between　incoherent　and　coherent　random　lasing.　The　phenomenon　derives　from　the　changing　of　light　scattering　properties　in　different　phase　states,　thus　affecting　the　optical　feedback　path　of　random　lasing.　Besides,　based　on　its　controllable　and　easily　detectable　time-domain　characteristics,　the　phase　transition　random　laser　is　applied　in　information　encoding　and　transmission.　It　is　the　first　time　that　the　transition　from　coherent　to　incoherent　random　lasing　is　observed　by　varying　the　sample　phase　states.　This　work　will　inspire　the　design　and　application　of　novel　random　lasers　in　photoelectric　device.　©　2023　Optica　Publishing　Group　under　the　terms　of　the　Optica　Open　Access　Publishing　Agreement.