A pair of degenerated primers was designed based on the conserved region of UCP2 among human, mouse, horse and dog. Then, cDNA fragments encoding the complete coding domain sequence (CDS) of UCP2 were amplified from three bat species (orders), Rhinolophus ferrumequinum (Rhinolophidae), Miniopterus fuliginosus (Miniopteridae) and Cynopterus sphinx (Pteropodidae). The CDS of UCP2 from three different bat species contain 930 bp encoding 309 amino acids. The deduced amino acid sequence of bat UCP2 consist three signature motifs of mitochondrial transporter protein and UCP-specific sequences. Our results showed that UCP2 gene of bats and other mammals shared high homology (90.6% to 97.0%). Evolutionary analysis indicated that UCP2 gene is highly conserved and has undergone strong purifying selected pressure during the evolution of mammals (ω=0.063). In addition, by comparing the difference of selected pressure on UCP2 between bats and other mammals, non-hibernating bats and hibernating bats, no significant difference was identified (P0.05). Taken together, all these data proved that UCP2 has an effect on the regulation of energy metabolism of mammal evolution. The mechanism of metabolic regulation of UCP2, however, remains unclear and further investigation is needed to clarify this process.