The activity of Horseradish Peroxidase (HRP) was enhanced with different strength of high voltage electric field. The results have shown that Ultraviolet-Visible spectra have been changed obviously. Experimental results indicate that the conformation of HRP can be changed by electric field. The study also showed that the activity index of HRP was increased by the certain strength of electric field. The activity index increase possibly was caused by the conformation variations of HRP. The result of this study has important meaning to explain the macroscopical electrostatic biological effects.