Objective:To investigate the relationship between serum leukocyte-associated immunoglobulin-like receptor 2 (LAIR2) expression and cellular immune function, prognosis in patients with non-small cell lung cancer.Methods:From April 2016 to April 2017, 90 patients with non-small cell lung cancer who were treated in Shangqiu first people’s Hospital were taken as the lung cancer group, and they were grouped into the survival group and the death group according to whether the patients died within 5 years. Another 84 patients with benign pulmonary mass were selected as the control group. The levels of CD4+[ (28.26±5.14) % vs (47.02±6.73) %], CD8+ [ (23.76±5.84) % vs (30.12±6.03) %] and CD4+/CD8+ [ (1.17±0.30) % vs (1.56±0.50) %] in peripheral blood immune cells were detected by flow cytometry; the serum LAIR2 level was detected by enzyme-linked immunosorbent assay (ELISA) , and the average serum LAIR2 level of patients with non-small cell lung cancer was applied as the boundary, and they were grouped into a low LAIR2 expression group and a LAIR2 high expression group; Pearson correlation was applied to analyze the correlation between serum LAIR2 level and immune cell level in patients with non-small cell lung cancer; Kaplan-Meier curve was applied to analyze the relationship between serum LAIR2 level and 5-year survival rate of patients with non-small cell lung cancer; and multivariate COX regression analysis was applied to analyze the factors affecting 5-year mortality in patients with non-small cell lung cancer.Results:The level of serum LAIR2 [ (69.55±13.12) ng/ml vs. (20.64±7.13) ng/ml] in the lung cancer group was significantly higher than that in the control group, and the levels of CD4 +, CD8 + and CD4+/CD8+ were significantly lower than those in the control group ( P<0.05) . The serum LAIR2 level in patients with TNM stage III+IV (77.32±13.09) ng/ml, poorly differentiated tissue (78.14±13.26) ng/ml, and lymph node metastasis (79.02±13.81) ng/ml was significantly higher than that in patients with TNM stage I+II (64.37±12.89) ng/ml, medium/well differentiated tissue (64.32±12.73) ng/ml, and no lymph node metastasis (62.92±12.85) ng/ml ( P<0.05) . The levels of CD4 +, CD8 + and CD4 +/CD8 + in the LAIR2 high expression group were significantly lower than those in the LAIR2 low expression group ( P<0.05) . Serum LAIR2 level in patients with non-small cell lung cancer was negatively correlated with CD4+, CD8+ and CD4+/CD8+ levels ( r=-0.510, -0.496, -0.494, P<0.05) . The 5-year survival rate of patients with high LAIR2 expression was lower than that of patients with low LAIR2 expression ( r=6.375, P<0.05) . LAIR2 was an independent risk factor for 5-year death in patients with non-small cell lung cancer ( P<0.05) . Conclusion:LAIR2 is highly expressed in serum of patients with non-small cell lung cancer, and its expression level is closely related to cellular immune function and prognosis.