We　characterized　ramie　leaf　β-amylase,　and　determined　its　thermostability　and　kinetic　parameters.　The　enzyme　was　purified　53-fold　using　ammonium　sulfate　fractionation　(40–60%　saturation),　anion　exchange　chromatography　on　DEAE-cellulose　and　gel　permeation　chromatography　on　Superdex-200.　The　purified　enzyme　was　identified　as　β-amylase　with　molecular　mass　of　42 kD.　The　enzyme　displayed　Km　and　kcat　values　for　soluble　potato　starch　of　1.1 mg/mL　and　7.8 s−1,　respectively.　The　enzyme　had　a　temperature　optimum　of　65 °C,　and　its　activity　at　70 °C　was　92%　of　that　at　the　optimal　temperature　after　a　15-min　incubation.　Furthermore,　enzyme　activity　was　stable　during　treatment　at　55 °C　for　60 min　but　was　inactivated　rapidly　at　＞75 °C.　This　thermal　behavior　indicates　that　ramie　leaf　β-amylase　has　excellent　intermediate　temperature-stable　enzyme　properties　for　the　baking　and　bio-industries.　Inactivation　of　the　enzyme　followed　first-order　kinetics　in　the　range　of　55–80 °C.　The　enthalpy　change　of　thermal　inactivation　(ΔH‡),　ΔG‡,　and　ΔS‡　were　237.2 kJ/mol,　107.7 kJ/mol,　and　0.39 kJ/mol K　at　333 K,　respectively.　The　D-value　at　65 °C　(= 110 min)　and　the　z-value　(= 9.4 °C)　are　given　for　food　processing.　©　2017　Elsevier　Inc.