It is formed by connecting the insect body with the fungal stroma growing from the insect head. The worm is like a silkworm, with a length of 3~5cm and a diameter of 0.3 ~ 0.8 cm. The surface is dark yellow to yellowish brown (the color of Cordyceps sinensis is dark), with 20~30 ring lines, and the ring lines near the head are fine; The head is reddish brown, with 8 pairs of feet and 4 pairs in the middle. Brittle, easy to break, slightly flat section, yellowish white. The submount is slender and cylindrical, 4~7cm long and 0.3cm； in diameter; The surface is dark brown to brown, with fine longitudinal wrinkles, and the upper part is slightly enlarged; The material is flexible and the cross section is white. The smell is slightly fishy and the taste is slightly bitter.

The insect body is yellow, shiny, plump and hypertrophy, the cross section is yellow and white, it is not hollow, and the pedestal is short, free from mildew and impurities.