Objective To explore the expression and clinical significance of GALNT2 protein in lung adenocarcinoma(LAC) based on data mining. Methods GALNT2 gene expression in LAC was analyzed using Oncomine database. UALCAN analysis platform was used to analyze the relationship between GALNT2 gene expression in The Cancer Genome Atlas (TCGA) and Clinical Proteomic Tumor Analysis Consortium (CPTAC) datasets and clinical features, and KM-plotter website was used to analyze the relationship between GALNT2 gene expression in LAC and prognosis. The mutations of GALNT2 gene in LAC from TCGA dataset were explored using cBioportal online analysis tools. The related protein networks were constructed for function enrichment analysis by using String database. Results The data in the Oncomine database showed that the mRNA expression and DNA copy number variation (CNV) of GALNT2 in LAC tissues were significantly higher than those in normal tissues (P<0.01). The transcription and protein level of GALNT2 in tumor tissues in LAC patients were significantly higher than that in marching tissues,but its expression level had no correlation with the clinical pathological characteristics of patients. A total of 52 samples of 503 LAC samples had GALNT2 gene mutation, and the mutation rate was about 10%. Survival curve analysis showed that the overall survival periods of GALNT2 high expression group and GALNT2 mutation group were shorter than those of GALNT2 low expression group and no mutation group (P<0.01). Multivariate Cox regression analysis showed that the high expression of GALNT2 was an independent risk factor of prognosis in LAC (HR=1.48, P=0.01). String database analysis revealed that GALNT1, RAB6A, RAB6B,DYNC1H1, DYNC1LI1, DCTNs, CAPZAs and mucins had obvious interactions with GALNT2, and these proteins were mainly involved in minus-end-directed organelle transport along microtubule, protein O-linked glycosylation via serine/threonine, O-glycan processing and IL-17 signaling pathway. Conclusions GALNT2 can be highly expressed in LAC tissues, has a high frequency of gene mutation, and may be related to poor prognosis of patients using data mining methods, thus providing a theoretical basis for further research on the role of GALNT2 in the occurrence and progression of LAC.