In December 2019, coronavirus disease 2019 (COVID-19) was detected in Wuhan and spread rapidly in China and some other countries and regions. World Health Organization declared it is a public health emergency of international concern (PHEIC) on January 30, 2020. Sequence and clinical analysis showed 2019 novel coronavirus (2019-nCoV) is the causative agent. 2019-nCoV is a single positive strand RNA virus with a genome of about 30 kb. The genome is composed of two untranslated regions at both ends and multiple encoding regions for non-structural proteins (NSPs) and structural proteins. ORF1a and ORF1b encode 16 NSPs. The structural proteins include spike (S) protein, envelope (E) protein, membrane (M) protein and nucleocapsid (N) protein. Understanding genomic structure and protein functions of 2019-nCoV would be helpful to explore 2019-nCoV’s traceability, replication and proliferation, pathogenic immunity, drug and vaccine development, as well as the current epidemic prevention and control.