The genus Cucumis includes about 70 species to date, and plants from this genus are found in 75 countries of Africa, Asia and Australia. The cultivated cucumber , which is important in daily diet, represented a narrow genetic diversity. The exploration and incorporation of elite and diversified genes, which were derived from wild relatives, are of great interest, in order to enrich the genetic basis of cultivated cucumber and the practical uses in breeding for new varieties. This review introduces the distribution and classification of Cucumis plants, the origin and discovery of the main wild relatives, the innovation of genetic resources between species, and finally emphasizes the research progress of the main wild species. Based on the expertise, the problems in the utilization of wild resources are summarized and the actions to improve and create novel cucumber varieties by incorporating wild resources are proposed. This work thus provides reference and guidance for the gene mining and genetic improvement of Cucurbits.