The serine deaminase from Escherichia coli K-12 MG1655 was recombinant expressed in Escherichia coli BL21 (DE3) using plasmid pET28a as vector. The enzymatic properties of recombinant serine deaminase were studied, and several influence factors of enzyme reaction such as temperature, initial pH, concentration of L-serine were investigated. Then DL-serine was resoluted with recombinant serine deaminase. The results indicated that the recombinant serine deaminase was successfully expressed, and the optimal conditions for enzymatic conversion of L-serine were 37oC, initial pH=9.0 and ? (L-serine) =4%. 0.3 g serine deaminase cell enzymatic conversion 100 ml ? (DL-serine) =8% needs 8 h, and the mole conversion rate of L-serine is up to 98%.