Nanobodies are a subclass of antibodies found in camels.They are multifunctional molecular binding scaffolds composed of a single polypeptide chain.The excellent performance of nanobody determines its wide application in the fields of biomedical and food science.Although the sequence and structure data of nanobodies are very large,the heterogeneity of their sources and the lack of standardization hinder the reliable collection of nanobody information.In order to effectively integrate the huge data of nanobodies that have been published at present,it is necessary to establish a nanobody database for immunoinformatics.We propose a nanobody structure database system NANO(http://124.221.201.63:8000/index).The NANO system collects and stores the information of 2 160 nanobody sequences and their structure.It provides basic search functions of text,sequence,amino acid region,and advanced search functions of species,affinity,and sequence length.Compared with the existing database systems INDI,PDB,NCBI and SAbDab-nano,the NANO system performs well in aspects of search field,search function coverage and search time performance.It can be used to screen or design high affinity nanobodies and promote the development of new nanobody specific calculation schemes.