The chemical synthesis of Guanine arabinoside(ara-G)is extremely complex,time-consuming,and se- riously polluted.A two-step enzymatic synthesis process was developed to acquire ara-G easily.2,6-Diaminopurine arabinoside(ara-DA)was first synthesized with purine nucleoside phosphorylase and pyrimidine nucleoside phosphorylase produced by Enterobacter aerogenes DGW-07.The conversion yield of ara-DA could reach above 90% when the reaction liquid contained 30 mmol·L- 1uracil arabinoside as arabinose donor,10 mmol·L -12,6-diaminopurine as arabinose acceptor in pH 7.0 20 mmol·L- 1phosphate buffer,and reacted at 60°C for 48h.Then,ara-DA was ef- fectively transformed into ara-G with adenylate deaminase produced by Aspergillus oryzae DAW-01.The total process had no complex separation and purification.