Objective:　To　screen　and　identify　mannanse　-producing　marine　microorganisms　and　characterize　the　enzyme.　Method:　2216E,　seawater-PDA　and　seawater-Gause＇s　Synthetic　Agar　Media　were　used　to　isolate　marine　microorganisms.　The　first　screening　of　mannanase-producing　microorganisms　was　through　plate　transparent　ring　method.　Furthermore,　morphological,　physiological,　biochemical　and　molecular　biology　methods　were　applied　to　identify　the　strains.　The　crude　enzyme　was　prepared　by　ammonium　sulfate　fractionation　to　analyze　theeffects　of　temperature,　pH　and　metal　icons　on　the　enzyme　activity.　Result:　There　are　467　bacteria,　145　molds　and　10　actinomycetes　strains　screened　from　the　sea-water　and　mud　samples　from　Taiwan　Strait.　Strain　B555　with　the　highest　enzyme　activity　of　28.18　U/mL　was　identified　as　Bacillus　sp.　The　mannanse　produced　by　strain　B555　showed　optimal　catalytic　activity　at　pH　7.0　and　50-55℃.　Its　half-life　is　approximate　150　min　under　55℃.　It　was　inhibited　by　Ni+,　Co2+,　Zn2+,　Mg2+,　Ca2+,　Na+,　K+,　Fe3+,　Ba2+　at　the　concentration　of　1　mmol/L.　At　55℃　and　pH　7.0,　the　Km　and　Vmax　of　the　mannanase　on　locust　bean　gum　were　4.7　mg/mL　and　588.23　μmol/(mL·min),　and　on　konjac　powder　were　3.33　mg/mL　and　476.19　μmol/(mL·min),　respectively.　Conclusion:　The　mannanse　will　be　valuable　for　Enzymatic　preparation　of　KOGM.　©　2015,　Editorial　Office　of　Journal　of　CIFST.　All　right　reserved.