With N,N′-dimethylpiperazine(DMPIP) as the structure-directing agent, a zinc phosphate [Zn6(H2O)· P5O20][C5N2H14][C6H16N2]0.5·3H2O(1) with a novel three-dimensional(3D) open-framework architecture was hydrothermally synthesized. Its structure was determined by single-crystal X-ray diffraction analysis and further characterized by ICP, NMR, and TG analyses. Compound 1 crystallized in the triclinic space group P1(No.2) with a=0.9984(2) nm, b=1.2354(3) nm, c=1.2384(3) nm, α=88.32(3)°, β=74.57(3)°, γ=75.81(3)° and Z=2. The alternation arrrangement of tetrahedral Zn units[ZnO4 and ZnO3(H2O)] and PO4 units forms an anionic 3D open framework containing intersecting 16-, 10- and 8-ring channels. Water molecules, diprotonated DMPIP, and diprotonated N-methyl-piperazine(MPIP) decomposed from DMPIP, are located in the channels and interact with the host framework via H-bonds. Compound 1 transforms to another new phase(compound 2) upon calcination at 200―350°C with the removal of the water coordinated to Zn atoms in the lattice. The phase transformation of compound 2 was further studied. With N, N’-dimethylpiperazine (DMPIP) as the structure-directing agent, a zinc phosphate [Zn6 (H2O) · P5O20] [C5N2H14] [C6H16N2] 0.5 · 3H2O (1) with a novel three- dimensional -framework architecture was hydrothermally synthesized. Its structure was determined by single-crystal X-ray diffraction analysis and further characterized by ICP, NMR, and TG analyzes. Compound 1 crystallized in the triclinic space group P1 (No.2) with a = 0.9984 (2) nm, b = 1.2354 (3) nm, c = 1.2384 (3) nm, α = 88.32 (3) °, β = 74.57 (3) °, γ = 75.81 (3) ° and Z = alternation arrrangement of tetrahedral Zn units [ZnO4 and ZnO3 (H2O)] and PO4 units forms an anionic 3D open framework containing intersecting 16-, 10- and 8-ring channels. Water molecules, diprotonated DMPIP, and diprotonated N-methyl- piperazine MPIP) are decomposed from DMPIP, are located in the channels and interact with the host framework via H-bonds. Compound 1 transforms to another new phase (compound 2) upon calcination at 200-350 ° C with the removal of the water coordinated to Zn atoms in the lattice. The phase transformation of compound 2 was further studied.