Crop germplasm is a discipline established in the 20th century, based on worldwide exploration and collection and the research on the phenotypes, and geographic distributions of diversities by Vavilov. The first modern crop gene bank was built in USA in 1958. Since then, more than 1300 crop gene banks have been built in the world. More than 6 million accessions (approximately 25 million accessions according to another document) are conserved in these gene banks. Gene banks can be Classified as three types： long-term, middle-term and short-term. Conservation in liquid nitrogen is an efficient method. Germplasms of vegetative crops are kept either in vitro or in field gene banks. Because of the more and more urgent need of crop germplasm in breeding and development of biotechnology, crop germplasm sciences enter a period which focuses on evaluation and identification of the collections. Molecular genetic mapes can not only be used to identify qualitative traits, but also be utilized to discover quantitative trait genes. The indigenous crop germplasm resources in China have been well collected. A national crop gene bank (a long-term bank) was built in 1986, in which more than 310 000 collections of all kinds of crops are conserved, and a duplicate long-term crop gene bank with the same collections was also built in Xining, Qighai Province. In addition, 22 middle-term banks (8 in the institutes of CAAS, and 14 in provincial academies of agricultural sciences), 30 national field gene banks and 2 in vitro gene banks have been established. Most of the collections have been preliminarily evaluated on agronomic traits, disease and pest resistance, stress tolerance and quality. All of the data have been documented in computers, and an information system about Chinese crop germplasm has been developed. With the development of biotechnology in the 21st century, it will be a hot point to discover new genes from germplasm resources via application of new technology. So it is essential to keep all these accessions well and prevent any gene from loss, and to introduce new crops and genes from abroad to promote the variety improvement and enhancement of agriculture system. I-dentification of new genes from land races, especially from wild species to enhance the sustainable development of agriculture will be the centre of germplasm work.