The tolerance of Lycium barbarum polysaccharide with a variety of biological activities is poor in the environment of gastric acid or intestinal canal, which leads the great weakening of to its biological activities. This defect can be modified by nano- encapsulation. Wolfberry polysaccharide nanocapsules are prepared by microemulsion technique and compound- agglomeration method. The particle sizes and distributions of these nanocapsules in liquid phase are measured by dynamic light scattering, which can analyze the stability of wolfberry polysaccharide nanocapsules in different simulation environments of gastric acid (pH=3.5), store (pH=5.5), dodecadactylon (pH=6.8) and large intestine (pH=7.4). The results show that, the polysaccharide nanocapsules can exist steadily in the environments of gastric acid, store, dodecadactylon and large intestine without standing time and in the environments of gastric acid and store within standing time of 5 h. However, the wolfberry polysaccharide nanocapsules become unstable in dodecadactylon with standing time of 2 h or in large intestine with standing time of 1 h. The above conclusions reveal that the prepared wolfberry polysaccharide nanocapsules have the effect of pH-controlled release.