The　effect　of　microwave　pretreatment　on　the　anaerobic　degradation　of　hyacinth　was　investigated　using　response　surface　methodology　(RSM).　The　components　of　lignin　and　the　other　constituents　of　hyacinth　were　altered　by　microwave　pretreatment.　Comparison　of　the　near-infrared　spectra　of　hyacinth　pretreated　by　microwave　irradiation　and　water-heating　pretreatment　revealed　that　no　new　compounds　were　generated　during　hyacinth　pretreatment　by　microwave　irradiation.　Atomic　force　microscopy　observations　indicated　that　the　physical　structures　of　hyacinth　were　disrupted　by　microwave　pretreatment.　The　yield　of　methane　per　gram　of　the　microwave-irradiated　substrate　increased　by　38.3%　as　compared　to　that　of　the　substrate　pretreated　via　water-heating.　A　maximum　methane　yield　of　221　mL.g-sub(-1)　was　obtained　under　the　optimum　pretreatment　conditions　(substrate　concentration　(PSC)　=　20.1　g.L-1　and　pretreatment　time　(PT)　=　14.6　min)　using　RSM　analysis.　A　maximum　methane　production　rate　of　0.76　mL.h(-1).g-sub(-1)　was　obtained　by　applying　PSC　=　9.5　g.L-1　and　PT　=　11　min.　Interactive　item　coefficient　analysis　showed　that　methane　production　was　dependent　on　the　PSC　and　PT,　separately,　whereas　the　interactive　effect　of　the　PSC　and　PT　on　methane　production　was　not　significant.　The　same　trend　was　also　observed　for　the　methane　production　rate.　(C)　Higher　Education　Press　and　Springer-Verlag　Berlin　Heidelberg　2017