Abstract: In the paper, insulin was taken as the model of heat-sensitive drugs, and LEA-motif as the bioactive protectant. Gromacs software with Gromos96 ( 53a6) forcefield was adopted to investigate the LEA- motif protective effects on insulin by REMD molecular simulation method. Results showed a significant protective effect on 3D structure and secondary structure of insulin with the presence of LEA- motif. In addition, the potency experiment by HPLC showed the bioactivity of the rehydrated insulin with LEA-motif was higher than that of the rehydrated insulin without any protectant. In a word, LEA-motif had shown its great application value as a drying protectant for heat-sensitive protein drugs.