To identify the important genes that affect the phenotypic differences between the Landrace and Debao pigs, especially the differences in metabolism and muscle growth. Differentially expressed genes of psoas major were detected by mRNA transcriptome sequencing in Landrace and Debao pigs. By extracting the total RNA of the psoas major muscle of the Landrace pig and the Debao pig, purifying the mRNA, constructing the cDNA library, conducting transcriptome sequencing, and then through the sequencing quality evaluation, we know that the sequencing quality of this study is relatively high. A total of 17,943 genes were detected in all samples, including 17,870 known genes and 73 new genes. Defined genes with |log2FC| greater than 2 and Q-value less than 0.001, and screened them as significantly differentially expressed genes. A total of 1661 differentially expressed genes were screened from the samples of Landrace pigs and Debao pigs, among which 1255 genes were differentially up-regulated and 406 genes were differentially down-regulated. Through differential gene analysis, it is concluded that these genes are mainly involved in metabolic regulation, muscle and fat development and other processes, especially some important functional genes such as MAPK14, FOS, SIRT1, KRAS, EGR1, CDNNB1, etc. To sum up, this study used transcriptome sequencing method, and then selected differentially expressed genes between Landrace pigs and Debao pigs through data analysis, and finally screened out important genes affecting phenotypic differences, which provided genetic support for breeding better breeds in the future.