Transporter associated with antigen processing 1 (TAP1), as an important candidate gene for disease resistance, plays an important role in body's immune process. In order to investigate the differential expression and possible regulatory mechanisms of TAP1 in each tissue at different growth stages, real-time PCR was used to detect the expression in 12 different tissues (heart, liver, spleen, lung, kidney, stomach, muscle, thymus, lymph node, duodenum, jejunum, ileum) of Meishan piglets at birth, 7 days, 14, 21, 28, and 35 days of age. The results showed that TAP1 was expressed in all sample tissues, and the expression level was the highest in lung, following by jejunum, duodenum, ileum. The expression of TAP1 gene was different in different tissues and increased in different ages. In the immune tissue, the expression of TAP1 gene was maintained at a high level; in the intestinal tissue, the expression of TAP1 gene increased with age, reached a significant level at 21 days, and decreased to a stable value at 21 days. The experimental results showed that the TAP1 gene was not tissue-specific in Meishan piglets. In addition, the expression of TAP1 gene was significantly increased in the intestinal tissues due to changes in the diet during the weaning period, indicating that the TAP1 gene may play an important role in the immune regulation process in intestinal tissues