This is a combination of experiments and three-dimensional numerical simulation approach to verify the simulation results of the molten zone shape by experimental data. We study the effect of CO2 laser heating ring and gravity field deviation caused by the space perturbation on micro-floating zone of LHPG during the fiber growth on comparing similar conditions and changing the input parameters of simulation. Our preliminary results compared with the molten zone shape are satisfied. The shape of the molten zone (especially the solid-liquid interface) by the asymmetrical heating effect is much larger than the result by gravity field in the simulation, which results in tilting by 3 degrees when the source rod diameter is below 500 mu m. The influence will decrease rapidly with the reduction of the source rod scale and diameter reduction ratio. These results will help us with the internal flow of the molten zone analysis and developing LHPG crystal fiber growth along the horizontal direction in future. (C) 2012 Elsevier B.V. All rights reserved.