The theoretical of the stress of capsule was analyzed in viscous liquid environment. and studied the dynamic characteris-tics of magnetic drive capsules with different sizes of round and oval heads under fluid-solid coupling in intestinal environment. The effects on the capsule exercise stress were also studied from the gut dynamic viscosity, the capsule size and capsule shape by COMSOL. According to the principle of similar mechanical properties, using superelastic solid material, the intestinal fluid model and the intestinal wall model were designed by multiple factors and levels of numerical simulation experiments. Results: At the same level of dynamic viscosity and intestinal wall dimension parameters, oval head capsule driving resistance decreased about 12.8% compared to that of circular capsule.