Ecosystem preservation and restoration of Mountain-River-Forest-Farmland-Lake-Grass System is very important for national ecological security. Current researches on ecosystem preservation and restoration for territorial spatial planning lack the determination and identification of key areas from a perspective of ecosystem integrity and landscape connectivity. Due to wetland degradation and homogeneity of habitat types that resulted in the low ecosystem resilience, it is urgent for in Yantai, a typical bay city in China, to restore degraded ecosystem and preserve natural resources. In the study, a regional ecological security pattern was proposed and key areas of ecosystem preservation and restoration including pinch points, barrier points, break points and fragmented ecological functional land were identified using habitat quality model, habitat risk assessment model, granularity inverse method, minimum cumulative resistance model and circuit theory. The results showed that the ecological hubs covered an area of 668.85 km2, with a total of 1548.36 km corridors between them, and most of the hubs were water body and forests. All of them constructed a "two horizontal and two vertical" ecological security pattern. Key areas of ecosystem preservation and restoration were identified based on the ecological security pattern, including a total of 13 ecological pinch points, 8 ecological barrier points, 39 ecological break points, and 1308.66 km2 of fragmented ecological land. Suggestions of restoration were proposed, with a combination of the spatial distribution characteristics and land use status of various key areas of ecosystem preservation and restoration. It would help to provide scientific guidance for identifying key areas of ecosystem preservation and restoration for territorial spatial planning and sustainable ecosystem management.