〔Abstract〕 The prokaryotic expression vector of Ltp1 was constructed by recombinant method, and transformed into E.coli BL21(DE3) for over-expression induced by isopropyl-β-D-galactoside(IPTG), then the target protein was coarsely purified by nickel column chromatography and fine purified by molecular sieve, and the product was expressed by SDS-PAGE electrophoresis and Western blot. The activity of the target protein was analyzed by color reaction with disodium p-nitrophenyl phosphate. SDS-PAGE results showed that there was an expression band consistent with its theoretical relative molecular weight. Western blot analysis confirmed that the protein was indeed a target protein with six histidine(His) tagswhich could catalyze the activity of phosphate monoester. The Michaelis constant(Km) and the maximum reaction rate(Vmax) were calculated to be 70.4 μmol and 51.1 μmol/(L·min) respectively, which had the highest catalytic activity at pH 5.0～6.0 and 37～50 ℃.