The aim of this study was to analyze T-cell lymphoma invasion and metastasis-inducing factor 1 (Tiam1) expression in lung cancer patients. A total of 204 patients with lung cancer tissue lesions were enrolled in the present study, along with 40 cases of normal lung tissue and 40 of normal fetal lung tissue. Tiam1 protein expression level was determined using intensity quantitative analysis, for comparison in lung cancer, metastatic, normal lung, and fetal lung tissue. The positive unit (PU) of Tiam1 was 13.5 ± 5.42 in lung cancer, 5.67 ± 1.56 in normal epithelial cells, and 5.89 ± 1.45 in fetal lung epithelial cells. The value in the lung cancer tissue was significantly higher than that in the normal lung tissue and the fetal lung tissue (P<0.01). The Tiam1 PU values with lymph node metastasis and without lymph node metastasis were 15.2 ± 4.34 and 12.5 ± 4.23, respectively, and the difference was statistically significant (P<0.05). The Tiam1 PU values in different tumor, nodes, metastasis (TNM) stages, III-IV period, and I-II phase were 14.7 ± 4.14 and 11.0 ± 5.34 (P <0.05). A correlation was found between Tiam1 expression and the age of patient, tumor size, tumor type, and tumor differentiation. Tiam1 protein expression in the lung tumor tissue is significantly higher than that in the normal lung tissue and fetal lung tissue. Tiam1 expression may be closely related to lung cancer development and metastasis.