Lysine-specific demethylase 1 (LSD1) functioned as a demethyl methylase gene, underlying a wide range of biological processes, including cancer, cell apoptosis, differentiation, and development. To further understand the functions of the porcine LSD1 gene, we first obtained cDNA sequence of porcine LSD1 gene, using in silico cloning method. We further found that the porcine LSD1 gene has two transcripts, in which cDNA sequences are 2,716 and 2,656 bp, ORF are 2,622 and 2,562 bp, respectively. Then, RT-PCR analysis showed that the LSD1 gene is expressed in various tissues and relatively higher in the tissues of ovary, kidney, and spleen. Besides, the LSD1 gene was expressed higher in the growth nonage and peaked at 3 days in muscle tissue. Meanwhile, the expression of two transcript variants of LSD1 gene presented the same change trend. Besides, the level of DNA methylation was approximately fourfold higher in a 3-day muscle than in an old pig (180 days), significantly positive related to the gene expression of LSD1 (R = 0.9362, P < 0.05), and declined with growing age. Cloning, expression pattern, and analysis with genome DNA methylation of porcine LSD1 gene laid a foundation to clarify the molecular mechanisms of porcine growth and development and also for further work on animal breeding.