The initial temperature field and mass transport during homoepitaxial AlN growth process by the PVT method were studied by FEMAG and in-house developed convection, mass transport, supersaturation and growth rate prediction finite element modules. The influences of the seed-holder shape on the temperature field, flow field, supersaturation and growth rate were investigated in detail by numerical simulations. The simulation results show that the flow and mass transport near the seed-holder were strongly affected by the axial and radial temperature gradient near the seed deposition surface, and these temperature gradients near the seed deposition surface could be calibrated by the expansion angle θ of the seed-holder. When the angle θ of the seed-holder is 130°, the temperature gradient at seed surface is small and the polycrystalline deposition at the seed surface and seed-holder periphery can be completely prohibited, which is beneficial to grow parasitic-free, crack-free and high-quality AlN single crystals.