The selective oxidation of butene to maleic anhydride has been carried out in a V2O5 coated membrane reactor. From the V2O5 sol made by fusing and melting, the V2O5 coated membrane with a uniform surface without crack is prepared on support. The mean pore diameter and specific surface area of the prepared membrane is 30 Angstrom and 1.1 m(2)/g, respectively. When the V2O5-coated membrane was heated to 450 degrees C, the V2O5 [010] plane was grown selectively, and at around 500 mm the charge was changed from O2- to V5+ in the selective oxidation reaction that produced maleic anhydride from butene. The maximum selectivity of 95% was obtained. This high selectivity shows that the V2O5 coated membrane reactor is very efficient for the selective oxidation.