Abstract With the continuous upgrading of high-throughput sequencing technology, a large amount of biological genome data has been deciphered and published. The research on functional genes of biological genomes urgently needs a collection of service websites with user-friendly and full annotation functions for a variety of gene function annotation tools. In this study, iCAZyGFADB, which is a database website integrating nine gene function annotation tools, was perfectly developed to meet the needs of biological genome functional annotation. Its nine gene function annotation tools were Carbohydrate-Active Enzymes (CAZyme) annotation, Gene Ontology (GO) annotation, Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation, Cluster of Orthologous Gene (COG) annotation, Evolutionary Genealogy of Genes: Non-supervised Orthologous Groups (eggNOG) annotation, SwissProt annotation, Pfam annotation, KOG annotation and Animal Transcription Factor DataBase (AnimalTFDB) annotation. It has three advantages. First, it is superior to gene function annotation of other biological cloud analysis platforms and runs very fast. Second, all gene annotation functions of the website are free and open to users. Third, it can annotate eight gene functions (GO, KEGG, COG, eggNOG, SwissProt, Pfam, KOG and AnimalTFDB annotation) of a single species at the same time, while other cloud platforms do not have the ability or need to charge to open for users to complete the annotation of eight gene functions at the same time. Moreover, the development and operation of our database will provide great help for gene function annotation research and significantly improve the efficiency of genome function research and reduce the cost of bioinformatics analysis. Genomic functional annotation researchers can access this database through the following website: http://www.icazygfadb.org.cn/. Database URL: http://www.icazygfadb.org.cn/