Abstract: Roof greening is an important indicator of ecological urban construction. In this paper, the necessity of roof greening is firstly expounded. On this basis, the irrigation water source for roof greening is categorized into five types; and the irrigation technologies are summarized into sprinkling irrigation, drip irrigation, filtration irrigation, and automatic irrigation. The applications of the abovementioned irrigation technologies are compared, and the development trend is prospected. Different roof types, the diversity of roof vegetation as well as regional differences should be considered in the design of roof greening. The technology of roof greening irrigation will develop towards irrigation automation, artificial intelligence, energy saving and control system diversification.

Key words: roof greening, ecological city, water saving irrigation, development status, automation