The expression of Snail in adjacent normal lung tissues, NSCLC primary foci and metastatic lymph node appeared upward tendency (P < 0.05), and the expression of Claudin-3 in adjacent normal lung tissues, NSCLC primary foci and metastatic lymph node appeared weakened (P < 0.05). The gene discussed is SNAI1; the disease is non-small cell lung carcinoma.