Along with the expansion of modern city, original villages located in the edge of city have been turning into isolated islands in flourishing city. Urban village, resulting from population boom in modern China, exists in major cities as common case. Architects propose a tentative idea of Green Cloud, aiming to improve rainwater management ability as well as providing green and comfort common place for residents, from which the current living states of residents could be improved. 'Green Cloud' is a low-technique required renovation method which can be copied easily. To make use of large quantity of roofs in urban village,architects build Urban Mountain on the roof which have potential to be reconstructed. Thicken the un-utilized roof and lists it into second land surface among which the rainwater is preserved and greening expanded (it could also be used as vegetables and plants planting). Such two dimensional land surface could change in Z axis according to space property.It creates pavilions for social activity beneath and upper space for people's walking and sitting.