Insulin, an intercellular signal molecular, plays a critical role in transferring life information. The studies on effects of pulsed electric fields on insulin molecular are meaningful for explaining the mechanism of biological effects of electromagnetic fields. The experiment results demonstrate that the conformation of insulin molecular has been altered by electric fields exposure for 30 minutes or by heat exposure for 50 hours. The results suggest that pulsed electric field exposure as heat exposure will after conformation of insulin molecular by breaking some hydrogen bonds and recombining another hydrogen bonds. The intercellular signal molecular may be an important target of electromagnetic fields.