The identification of ecological source in the traditional ecological network construction mostly considers the quality and area of habitat patches, but seldom considers the impact of ecosystem service function and spatial structure. Moreover, the traditional ecological network is mostly constructed in a relatively closed unit with only one scale, lacking nesting coordination, which will lead to the dislocation of ecological network structure between scales. To solve the above problems, an "Attribution-Function-Structure" index system is constructed to identify the ecological sources comprehensively. The Least-cost path method, the Circuit Theory and the Cyclic Window Search Method are adopted to form and identify ecological corridors, pinch points and barrier points respectively. From the Xuzhou metropolitan area and main urban area, two-scale ecological networks are constructed and overlapped to analyze its nested structure and coordination degree. The results showed that: (1) The coincident source areas at two scales is 79.85 km2, the overlapping corridors length is 158.42 km, and overlapping corridors area is 45.68 km2, which are important for the stability of the multi-scale ecological network connection and need to be protected. Meanwhile, 8 corridors that are vital to the metropolitan area but lack the underbelly support within the main urban area should be repaired as a priority. (2) A total of 17 and 18 pinch points are identified in the metropolitan area and the main urban area respectively, 10 of which overlapped; 8 and 10 barrier points are identified respectively as well, 5 of which overlapped. Contact ratio indicates that high migration resistance and large optimization potential coexist in key biological migration areas, which is in urgent need of repair. And the continuity of biological processes across scales need a multi-scale cascade framework to solve ecological problems coordinately. (3) Based on the theory of "Patch-Corridor-Matrix", a multi-scale nested ecological network optimization strategy is proposed from the three points about "Point-Line-Polygon". The research results can provide references for the regional ecological security pattern construction, land consolidation and ecosystem restoration.