Abstract: Identification of the larva stage of aquatic insects is one of the most important factors in biomonitoring water quality.So far,the morphological diagnostic character for many mature and early instar larvae are still lacking in China.The partial sequences of the mitochondrial COⅠ,COⅡ and tRNA gene of the adults and larvae of 4 species from Lepidostomatidae were sequenced and compared in this study.The results indicate that intraspecific divergence is <1% between the adult and larva and the interspecific divergence is 14%-24%.The study proves that the mitochondrial DNA sequence analysis is a useful tool to associate the larval and adult stages of Trichoptera,in turn;it will be valuable for health assessment of stream ecosystems.