With the fast increasing of urban underground space developments in China, a new kind of underground construction, deep excavation group, has been developed, which means a group of adjacent / related excavations constructed at same time or the supper large excavation divided into small pits. In this paper, the concept and characters of the deep excavation groups are introduced with cases in Shanghai. The excavation groups are divided into three kinds according to the special relation between different parts, which are divided excavation group, jointed excavation group, and adjacent excavation group. Some key scientific issues for further studies about excavation groups are also presented and discussed, i.e., soil behavior and constitutive model, earth pressure under limited soil zone, performance of dividing walls, coupling and interactive behavior of excavation group, environment response and control of excavation group, and huge scale computing method.