Abstract: Rapid urbanization has promoted the socio-economic development in recent years. However, a series of issue has also triggered to hinder the improvement of urbanization development quality, such as the shortage of cultivated land resources, the escalation of spatial conflicts, the deterioration of ecological environment, and the reduction of ecological service functions. A great challenge has posed on the regional sustainable development. It is a high demand to explore the relationship between urbanization and ecological environment, particularly with the national development strategy of new urbanization and ecological civilization construction. Some suggestions are of great significance for the coordinated development in the regional high-quality development. Taking Jiangsu Province of China as an example, this study aims to firstly construct the evaluation systems of urbanization and ecological environment from the perspective of the index value. The specific level and coupling coordination degree of urbanization and ecological environment were calculated from 2000 to 2020. Then, a systematic analysis was performed on the expansion of urban construction land and the importance of ecological environment protection from the perspective of spatial pattern. The spatial conflict index was finally determined to clarify the spatial layout conflict between urban construction land and the importance of ecological environment protection. The results show that: 1) The specific level of comprehensive urbanization and ecological environment was improved significantly after numerical coupling calculation. The urbanization level showed the spatial distribution characteristics of “high in the south and low in the north”. By contrast, there was no aggregation in the spatial distribution of ecological environment. Furthermore, the coupling and coordination between urbanization and ecological environment were presented with a spatial distribution pattern of “high in the south and low in the north”. Specifically, Southern Jiangsu was belonged to the type of “high coordination-lagging ecological environment”, Central Jiangsu and Xuzhou with the type of “medium/high coordination-lagging urbanization”, and Northern Jiangsu was the type of “basic coordination / imbalance -lagging/ hindering urbanization”. 2) Spatial conflict diagnosis showed that the expansion range of urban construction land reached 203.65%, with the largest expansion intensity in Suzhou and the smallest in Yancheng. The importance of ecological environment protection was mainly at lower and medium levels. The areas with the high importance of ecological protection were concentrated in Hongze Lake, Taihu Lake, and other water bodies, low-lying plains and low hilly areas. The intensity of spatial conflicts showed a trend of first decreasing and then increasing, with an average value increasing from 0.154 to 0.160. Therefore, the spatial characteristics of the west were greater than those of the east, while the north was greater than the south. 3) Some suggestions were proposed for the coordinated regional development. Southern Jiangsu should improve the level of ecological environment, according to the short board indicators, such as the industrial emission and domestic pollution. The expansion of construction land should be strictly standardized in Nanjing and Zhenjiang, due to the significant spatial conflict. The level of urbanization in the Central and Northern Jiangsu was still needed to be improved. Among them, the significant spatial conflict was found in Yangzhou, Taizhou, Xuzhou, Lianyungang, and Suqian. The expansion direction of construction land should be reasonably guided to strictly delimit three zones and three lines, in order to strengthen the space control, and steadily promote the moderate expansion of construction land. The findings can provide the quantitative reference and decision-making basis for the coordinated development of urbanization and ecological environment in Jiangsu Province. The research gap was fully filled in the relationship between urbanization and ecological environment from the index level. The dual perspectives of index value and spatial pattern were also integrated for the differentiated and coordinated development strategies with the provincial situation.