Abstract: The purpose of this study was to analyze the molecular characteristics of ApoA1 gene in Bos grunniens and detect its expression in different tissues, so as to provide theoretical basis for further study on the function of ApoA1 gene. Using yak liver cDNA as template, the coding region sequence（CDS） of ApoA1 gene was amplified by PCR and cloned; the mRNA expression levels of ApoA1 gene in heart, muscle, liver, spleen, lung, kidney, uterine horn, fat and fallopian tube were detected by RT-qPCR. The results showed that the CDS region sequence of ApoA1 gene was 798 bp, encoding 265 amino acids. The molecular weight of ApoA1 protein was 30 324.414 and its theoretical isoelectric point was 5.71. The secondary structure of protein was mainly composed of two parts α-Spiral（93.58%）. The Bos grunniens ApoA1 protein was an unstable hydrophilic protein with signal peptide, which was a secretory protein without transmembrane structure. The nucleotide sequence of ApoA1 gene in Bos grunniens had the highest similarity with the corresponding sequence of Bos taurus（99.64%）. Tissue expression profile analysis showed that ApoA1 gene was expressed in different tissues of yak, but the highest expression level was in liver, which was significantly higher than that in other tissues（P＜0.05）. These results of this study provide a theoretical basis for further research on the structure and function of ApoA1 gene and the genetic improvement of quality traits.