Through investigating the flora of the ruderal in the urban area of Shanghai, this paper analyzed the diversity of ruderal influenced by rapid urbanization, and studied the charateristics of ruderal adapt to the urban habitats with high heterogeneity. In the investigated 260 quadrats of ruderal community,107 species of ruderal were found to be belonged to 89 genera and 32 families. Gramineae and Compositae,the largest families,played a major role in these quadrats. High proportion of monotypic genus indicates that the heterogeneity of urban habitat is high. On the base of ruderal with wide adaptability adapt to urban habitat universally, the strategy of annual vegetation adapt to high strength and frequency man-made habitats is of short life cycle and strong adaptability. Special arid habitat in urban area increases the proportion of winter annual.