[en] In order to analyze the far-field temperature gradient, a finite element analysis (FEA) of the heat transfer in hollow micro-sphere filled with ICF fuel was made, providing the border adiabatic, meshing the model intellectualizedly, and supposing the parameter as 3, the cell as triangle. When the work temperature of the target was 24 K, in order to maintain the balance of the gas bubble in the micro-sphere, the temperature gradient in the target was 14.02 K/cm. The digital simulation result showed that the external temperature gradient was 7.75 K/cm. The result fits well with the data achieved by experiment. This shows the mathematics model is credible, and can be applied in the manufacture of the cryogenic target. (authors)