Abstract: The external morphology of the digestive tract of six species of locusts belonging to 3 families, the structure of the inner wall of anterior stomach and cardia were studied by physiological anatomy and electron microscope scanning techniques. The results show that digestive tract morphological and structural differences were found between famlies, especially in the ultrastructure of the inner wall of the foregastric and cardia. The foregastric and cardia of the plantar locusts belonging to the family Pteroptera are more developed than other species, which is typical polyphagous locust. The short-winged locust of the family Catantopidae, which mainly feeds on sagebrush in Compositae, the attachment mode of teeth on the inner wall of the foregastric, the angle of the tip of teeth on the inner wall of cardia are different from the other five species, which feed on grasses. It shows that although the morphological structure of the digestive tract is different between families, the structure of the digestive tract between grasshoppers in different families with similar diets is similar. It can be seen that the differences in the morphological structure of the digestive tract are closely related to the diet and adapt to each other.