BACKGROUND: Thymoma is the most common malignant tumor in anterior mediastinum, and its specific pathogenesis is still unclear. This limits the study of targeted drugs for thymoma. The aim of the study is to investigate the genes and signal pathways of thymoma, and provide help for the research of thymic tumor pathogenesis using the technology of second-generation genechip to analyze thymoma. METHODS: From January 2015 to December 2017, we analyzed 31 cases of thymoma by CapitaBio mRNA expression profile genechip technology, and then confirmed the genes by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: We found some genes with different expression levels between thymoma and surrounding thymus tissue. Among them, six driving genes (FANCI, CAPD3, NCAPG, OXCT1, EPHA1 and MCM2) were significantly abnormal in thymoma. Some specific genes affected by copy-number variation were detected: E2F2, EphA1, CCL25 and MCM2 were significantly up-regulated, while IL-6, CD36, FABP4, SH2D1A and MYOC genes were significantly down-regulated. KEGG database analysis showed that the expression of 10 signaling pathway genes was generally up-regulated or down-regulated, such as systemic lupus erythematosus, viral oncogenes, primary immunodeficiency, cell cycle genes and p53 signaling pathway, which may be related to occurrence of thymoma. CONCLUSIONS We found a variety of genes abnormally expressed in thymoma, which will provide reference for the study of pathogenesis and biomarkers of thymoma in the future.