 A dinuclear polyoxovanadate cluster Sr2V2O7·H2O was synthesized by hydrothermal reaction, and characterized by single-crystal X-ray crystallography, inductively coupled plasma (ICP-AES), and FTIR analysis. Sr2V2O7·H2O crystallizes in the monoclinic space group C 2/c with a = 14.8631(14) Å, b = 7.0433(7) Å, c = 14.9872(12) Å, β = 151.389(4)°, V = 751.30(12) Å3, Z = 4, Mr = 407.14, Dc = 3.599 g cm−3, F(000) = 752, λ(Cu/Kα) = 1.54178 Å, μ = 16.537 mm−1, GOOF = 1.092, R1 = 0.0330 for 850 observed reflections with I > 2σ(I) and wR2 = 0.0890 for all data. Sr2V2O7·H2O consists of one [V2O7]4− anion, two Sr2+ counter cations and one lattice water. The V2O74− anion has two VO4 tetrahedra linked by one µ2-oxo, other terminal V–O (µ1-oxo) bonds are all double-bonded. The results of DFT calculation are in agreement with the observation.