The gene special primers (GSP) were designed based on the short wavelength-sensitive (SWS) Opsin genes of primates, mice, cow and dog. Rapid amplification of cDNA ends (RACE) were used for amplifying 5′ end and 3′ end sequences of SWS Opsin gene of Myotis ricketti. The results show that the gene contains 1 050 bp in the coding region, encodes 350 amino acids, and lacks premature stop codons. In comparison with other mammals, the functionally important seven-transmembrane regions of the SWS Opsin gene are highly conserved, suggesting that it is a functional gene; and the key functional sites are 52 T, 86 F, 93 T, 114 A and 118 S, respectively, implying that the SWS Opsin of M.ricketti is sensitive to the ultraviolet (UV) light. Evolutionary analysis shows that positive selection has imposed on SWS Opsin in mammals, and the evolutionary rates of this gene have significant differences between M.ricketti and other mammals inferred by relative ratio test. Our study suggests that the SWS Opsin of M. ricketti have functional specialization, and thus may play an important role in bat vision in the night.