Golden grey mullet (Liza aurata) and leaping mullet (Liza saliens) are two species from Mugilidae which inhabit the Caspian Sea. Despite the difference in the number of Pyloric caeca, lateral line scale, and gill rakers, diagnosis between two species regarding morphological plasticity is relatively difficult. In this experimental study, in addition to access previous morphological diagnostic characters, 31 morphometric and 10 meristic characters were surveyed. Also, COI gene sequence used to confirm accurate identification of these two commercial species in the Caspian Sea. In this way 25 samples were used for biometry. Samples were collected from Nur and Anzali cities beach sein fishing center in autumn and winter 2016. Among surveyed morphological characters, 3 meristic and 15 morphometric characters revealed a significant difference (p<0.05), respectively. Regarding the principal component analysis (PCA) results, Pre-pectoral fin length, Pelvic fin length, Anal fin base length, Caudal peduncle width, Anal fin height and Head width, within Morphometric characters and Second dorsal fin rays, lateral line scale number, number of Gill rackers and Pyloric caeca were among meristic characters which reveals highest load factor (>0.7) in discrimination of two species specimens. Regarding genetic distances, the between-group distance estimated 40bp (6.8%) or 0.078 K2P that well agreed with morphological identification. Results revealed the application of more morphological characters in the diagnosis of two Mullet species in the Caspian sea which could be useful in completing identification keys.