Investigations were made on the structure and catalytic activity of vanadyl pyrophosphate. The structure of α,β, and γ-(VO)2P2O7 were determined means of IR spectroscopic method. The catalytic activity decreases in the following order β>γ>α, while the selectivity to MAA increases β>γ>α. The catalytic properties of (VO)2P2O7 depend on the arrangement of pyrophosphate ions in their crystals. Addition of phosphorus to β-(VO)2P2O7 prevent the complete oxidation of butane.