In the natural environment, various microorganisms are mainly responsible for the degradation of phthate acid esters. phthate acid esterase is one of key enzymes in the degradation pathway. A dibutyl phthalate esterase from Arthrobacter sp. ZJUTW was purified at 45-70% saturation with ammonium sulfate, ion-exchange chromatography (IEC) on Sepharose Q-XL column and hydrophobic interaction chromatography (HIC) on Hiprep Octyl FF column. The purified enzyme appeared homogeneous on SDS-PAGE, and its molecular weight was estimated to be 56.17 KDa. The optimal pH and temperature were pH 9.0 and 35 °C, respectively. The enzyme was stable in a pH range from 7.0 to 9.0 and below 25 °C. The enzyme activity was stimulated by Mg²⁺, but inhibited by several metals such as Cu²⁺, Zn²⁺, Ba²⁺, EDTA, and strongly inhibited by Fe³⁺. The K_m for DBP of the enzyme was 0.487 mmol/l, V_max was 223.3 ìmol/min·l.