The reasonable, orderly structure of ecological space is a guarantee for the survival and development of the region. The construction of provincially ecological security pattern and the optimization of ecological space structure are conducive to improving the carrying capacity of ecological environment, promoting the cooperative and reciprocal relationship between social economy and ecological environment to achieve sustainable development. Taking Guangdong Province as an example, this paper identifies the important ecological sources of Guangdong Province by means of the importance-sensitivity ecological assessment method, identifies the important ecological corridors by using the minimal cumulative resistance (MCR) model, constructs the ecological security pattern, and puts forward strategies for the adjustment and control of the ecologically spatial structure. The results showed that: (1) the area of important ecological source was 54636.77 km², accounting for 25.04% of the land area of Guangdong Province. (2) The ecological sources identified by the institute were highly coincident with the ecological protection red line and natural protection area in Guangdong Province. Eight-seven important ecological sources were selected based on the natural protection area and ecological sources. (3) The total length of ecological corridor in Guangdong Province was 7400 kilometers, and surrounding area of the corridor was mainly woodland. (4) The ecological space of Guangdong Province was mainly surrounded by the ecological barrier around the Pearl River Delta and the peripheral ecological barrier. The area and ecological importance of the ecological barrier around the Pearl River Delta were slightly higher than the peripheral ecological barrier. This research will help protect the key ecological space, and provide a reference for policy-making in order to improve the sustainable development of Guangdong Province.