Abstract: Urban ecological background values include two aspects: nature ecological background values and human ecological background values. The higher urban ecological background values are, the lower cost of developments and management urban ecosystem environment image are. The degree of dryness , the temperature in the coldest month, plant productivity, precipitation, daily precipitation and topography are used to measure nature ecological background values. The usual 7 indexes of western society, namely, society moral consciousness, public awareness, choice tradition value, custom habits, knowledge distribution, time budget and, culture and art are used to measure human ecological background values.The paper analyzes the correlative factors of urban ecological background values and grades them. The analysis of fourteen super metropolis of China showes that their urban ecological background values are widely discrepant. According to synthesis score, none of the fourteen cities are measured up to the first grade, one (Guangzhou) to the second, one (Shanghai) to the third, seven(Nanjing,Kunming,Chongqing, Chengdu,Wuhan, Beijing and Xi'an) to the fourth, three(Tianjin, Harbin and Shenyang) to the fifth and two (Lanzhou and Urumqi) to the sixth. According to the natural ecological background value score, none of them are measured up to the first grade either, with only Guangzhou to the second and Shanghai to the third, five(Chongqing, Wuhan, Chengdu, Nanjing and Kunming)to the fourth, three(Xi'an, Shenyang and Tianjin) to the sixth, two (Harbin and Beijing) to the seventh, one (Lanzhou) to the eighth and one (Urumqi) to the ninth, and the fifth grade is vacant. According to the human ecological background value score, none is measured up to the first grade, with only Beijing city to the second, seven(Shanghai, Nanjing, Kunming, Xi'an, Harbin, Guangzhou and Tianjin) to the third and the other six(Chengdu, Shenyang,Lanzhou, Urumqi, Chongqing and Wuhan) to the fourth. On the basis of urban ecological background values, the paper analyses in detail why Guangzhou city that has ever been an "unlivable city" could win the title of "international garden city".