Abstract: Based on field experiment and meteorological data, adequacy rate of rainfall for crop growth, coping capacity of rainfall with crop water requirement, water ecological adaptability and crop water use efficiency (WUE) were investigated. Farm household surveys and mathematical models were used to systemically analyze water consumption of main crops in Beijing metropolis. The results show that water ecological adaptability for the main corps in Beijing metropolis is in the following sequence: irrigated summer soybean＞irrigated spring soybean＞arid spring soybean＞arid spring millet＞irrigated summer corn＞irrigated spring corn＞arid spring corn＞arid potato＞arid alfalfa＞irrigated rice＞irrigated alfalfa＞irrigated winter wheat. WUE sequence is: irrigated alafalfa＞arid spring corn＞arid alfalfa＞irrigated spring corn＞arid spring millet＞arid spring soybean＞irrigated spring soybean.