Liver cancer is one of the common malignant tumors with high clinical mortality. Discovering new targets and developing new drugs are essential for the treatment of the disease. This study analyzes the differentially expressed genes related to the occurrence and development of liver cancer from the perspective of biological function and network， aiming to screen out molecular markers and immunotherapy targets for early diagnosis of liver cancer. First， two sets of liver cancer-related gene expression data are screened for differential expression. Then through GO （Gene ontology） function and KEGG （The kyoto encyclopedia of genes and genomes） pathway analysis， 128 target genes that are significantly enriched in the main functions and signal pathways are obtained. Finally， through the gene regulation network to explore the interaction law of target genes， ten key genes are identified and survival analysis is performed to verify that four genes of CYP3A4， CYP3A5， CYP2C9 and CYP2C8 are suitable as liver cancer markers or targeted therapeutic targets. This study provids a reference for the mechanism study of the occurrence and development of liver cancer， the screening of tumor markers and the selection of drug targets， and provide a basis for further related functional research.