From the researches in the past decade, we have found that acupuncture can effectively enhance the immunity. For the efficacy of acupuncture in enhancement of immunity, we introduce an aspect, in which human body considers the acupuncture as an acute stress to react the trigger of mechanism for enhancement of immunity. Facing the adversity, the body can enhance the immunity by over-mobilization to prepare for following greater harms. Acupuncture sometimes will result in a wound and the needles may stir deep nerve in twirling. The body will interpret the enormous wound. The trauma is a very important acute stress, which will trigger the anti-bacterial mechanism. Acupuncture is an acute stress since they have the same mechanism. The acute stress will enhance immunity through autonomic nervous system (ANS) and acupuncture does the same way. Both acute stress and acupuncture can activate the ANS axis and modulate immunity system throughout the limbic system, including the extended amygdale.