It is believed that visual exposure to nature in the interior environment can make human healthier. But little about the effect of visual environment on human health is known. This article employs some existing evidences that perceptual experience of natural elements in the interior environment could reduce mental fatigue. The results of this article are shown as follows: First, the perception of natural elements is a physiological activity in terms of psychological health. Secondly, the visual stimulation of nature provoking proper arouse helps psychological balance. The aim of this article is to provoke further thinking and research on this possibility that visual exposure to nature may make people healthier.