Abstract: This paper deals with compositions of both the pupa and moth of Dendrolimus houi. The contents of protein and chitin of pupa are 581.8 g/kg and 74.7 g/kg respectively,being lower than those of the moth 683.0 g/kg and 178.3 g/kg;while the pupas fat and carbonhydrate are obviously higher than those of the moth.Both the pupa and moth have 15 amino acids(tryptophan not attempted).The carbonhydrate in pupa is 5.21 times as much as that of the moth,demonstrating that a quantity of carbonhydrate is used up in the process of molting;and fat content of pupa is 225.2 g/kg,being 3.42 times of that of the moth;of all the fat acids,the change of linolenic acid from pupa to moth is noticeable.