The　process　improvement,　a　pilot　remediation　test　and　the　decontamination　mechanism　of　microwave-induced　steam　distillation　(MISD)　for　petroleum　hydrocarbons　(PHs)　removal　were　conducted.　Processes　of　multistage　steam　distillation　and　carbon　reinforcement　were　compared　to　determine　the　best　remediation　process.　Pilot　project　was　then　carried　out　to　explore　the　applicability　of　MISD　in　site-scale　remediation.　The　remediation　efficiency,　procedures　and　influencing　factors　of　site-scale　MISD　project　were　studied　by　monitoring　variations　of　soil　moisture,　temperature　and　PHs　concentrations.　Furthermore,　the　decontamination　mechanisms　of　PHs　were　clarified　based　on　kinetic　analysis.　The　results　showed　that　the　multistage　steam　distillation　could　improve　10%∼15%　remediation　efficiency,　and　the　carbon　reinforcement　could　shorten　remediation　duration　of　each　steam　distillation　stage　by　50%.　Pilot　MISD　project　adopted　multistage　steam　distillation　process　and　went　through　four　(initial,　rapid　heating-up,　gentle　heating-up　and　quasi-equilibrium)　remediation　stages　(overall　temperature　≤100　°C).　The　final　PHs　removal　rate　was　about　60%,　which　would　get　better　with　greater　proportion　of　low　boiling　points　components　and　stronger　vapor　extraction.　Kinetic　studies　showed　that　PHs　was　removed　by　steam　stripping　and　limited　by　intraparticle　diffusion　in　the　＇steam　distillation　zone＇,　while　local　high　temperature　(100　°C)　greatly　improved　PHs　volatilization　and　provided　activation　energy　for　PHs　desorbed　and　degraded　in　the　＇selective　heating　zone＇.　©　2022　Elsevier　Ltd