Abstract:[Objectives] Pulmonary surfactant (PS) can help to maintain the structure of alveoli, improve respiration and oxygen absorption and utilization. Notably, phosphatidylcholine (PC) serves as the principal constituent of pulmonary surfactant phospholipids. In order to shed lights into the adaptation mechanism of plateau animals to hypoxic environments, this study focuses on the endemic species of Plateau Zokor Eospalax baileyi and Plateau Pika Ochotona curzoniae in the Qinghai Tibet Plateau. [Methods] The sequences of Chok-α, Chok-β, Pcyt-α, Pcyt-β and Cpt genes were analyzed by MEGA 7.0, PAML 4.8 program and Ancestor program. Additionally, the mRNA expression levels of these genes were determined with Real-time PCR in the lung tissues and compared with those in the SD Rat Rattus norvegicus. [Results] The bioinformatics analysis revealed that the sequences of Chok-α, Chok-β, Pcyt-α, Pcyt-β and Cpt in E. baileyi were highly homologous with those of Nannospalax galili, as well as the O. curzoniae has the highest level of homology with O. princeps (> 90%) (Table 2). Cpt of E. baileyi and N. galili, Chok-β, Pcyt-β and Cpt of O. curzoniae and O. princeps occurred convergent sites. Selection pressure analyses showed that lysine at sites 4, phenylalanine at sites 5 and glutamic acid at sites 10 of Chok-α subunit in Plateau Zokor were significantly different (P < 0.05, Table 3); methionine at sites 4 of Chok-β subunit in Plateau Pika, glutamic acid at sites 163 of Cpt subunit in Plateau Zokor were also significantly different (P < 0.05, Table 3). SIFT test showed that No. 212 variation sites of Chok-β subunit and No.18 variation sites of Pcyt-β subunit in Plateau Pika had significant effects on gene function (P < 0.05, Table 4). The mRNA expression levels of Chok-α, Chok-β, Pcyt-α and Pcyt-β in Plateau Zokor were significantly higher than those in Plateau Pika and SD Rat (P < 0.01), and the mRNA expression level of Chok-β in Plateau Pika was higher than SD Rat (P < 0.05) (Fig. 6). The expression level of Cpt in SD Rat was significantly higher than that in Plateau Pika and Plateau Zokor (P < 0.01), while there was no difference between expression levels in Plateau Pika and Plateau Zokor (P > 0.05) (Fig. 6). [Conclusion] The above results demonstrate that, in comparison to SD Rat, the amino acid structure and gene expression variations of key enzyme genes in phosphatidylcholine pathway of Plateau Zokor and Plateau Pika, along with two plateau animal physiological adaptation make them more conducive to acquire and employ oxygen in the unique environment of high cold and hypoxic environment. Consequently, this reinforces respiration, enhances energy metabolism, and facilitates adaption to low oxygen environments.