Abstract: Elaphe perlacea belongs to Elaphe,Megapodiidae.Stejneger collected a male specimen in Ya'an and named it Elaphe perlacea in 1929.The number of Elaphe perlacea is rare,and its distribution areas are limited.Elaphe perlacea is the least studied species of Elaphe.Elaphe mandarinus also belongs to Elaphe,and it was named in 1882.Due to the similarities in heads and tails of both species and the limited information,it is difficult to differentiate the two species.In 2010,a specimen of Elaphe perlacea was collected in Fengtongzhai Nature Reserve of Ya'an.We obtained DNA sequence data of Elaphe perlacea (complete sequences of the mitochondrial NADH dehydrogenase subunit 4ND4 gene,cytochrome b gene and 12S rRNA partial sequences) and established phylogeny trees to examine the relationship of Elaphe species.The phylogenetic tree showed that Elaphe perlacea and Elaphe mandarinus were sister species,but also two valid species.And we also examined the morphological characters of Elaphe perlacea and Elaphe mandarinus,and found that there were stable differences between them.