Effective identification of important ecological function areas plays an important role in maintaining regional biodiversity and improving ecosystem services. Considering the strategic needs of the systematic conservation of mountains-rivers-forests-farmlands-lakes-grasslands and the lack of previous research on flexible ecological protection, this paper systematically analyzed the inherent requirements of flexible ecological protection space based on the concept of ecological protection under the sustainable development goals. Based on the perspective of ecosystem services, the consideration of important ecological functions and regional characteristics, this paper took the coastal characteristic development zone-Maoming City of Guangdong Province as the research area to select five ecosystem services, including climate regulation function, food supply function, biological protection function, water conservation function, and soil protection function as protection objects. This paper has obtained the ecological protection space through improved MARXAN model, and further verified the effectiveness of research results. The research results show that:① there are differences in the spatial distribution of various ecosystem services in Maoming. The high-value areas of comprehensive ecosystem services are mainly distributed in the northern mountainous areas, and the low-value areas are mainly concentrated in the southern urban construction area. ② The systematic conservation planning method which took into account the constraints and the protection costs had certain advantages in the delineation of ecological protection space. The ecological protection red line area in the systematic conservation planning result is 1505.02 km², accounting for 83.43% of the ecological protection red line area. The rest area is mainly composed of forest and grassland, garden land, and cultivated land, accounting for 45.92%, 19.71%, and 22.24%, respectively. ③ In the future ecological protection construction, the diversified remediation strategies such as enhanced management of ecological protection, comprehensive improvement of ecosystem services, and construction of ecological agriculture should be carried out for the core ecological red line, general protected areas, and basic farmland areas in the systematic conservation planning.