We investigated skin thermal changes after acupuncture stimulation for Meridian mechanism. So non-acupuncture group, acupuncture at left LI4 and acupuncture at left, right acupuncture group were observated in 0 min, 5 min and 10 min. And results was acupuncture group of left LI4 was increased in 0 min, 5 min and 10 min significantly. We proposed that increasing thermal changes was caused by Meridan and Gi reaction.