Exploring the relationships between landscape pattern and ecological processes is the key topic of landscape ecology, for which, a large number of indices were developed, as well as landscape pattern analysis model. However, one problem faced by landscape ecologists was that landscape indices were hardly to be linked with the ecological processes. How to link landscape pattern and ecological processes become a big challenge for landscape ecologists.“Source” and “sink” are a common concept used in air pollution research, by which the movement direction and pattern of different pollutants in air can be clearly identified. As for any ecological processes, it cam be considered as the balance between the source and the sink. Thus, the concepts of “source” and “sink” could be employed to the research of landscape pattern and ecological processes. In this paper, a theory of source-sink landscape was proposed. The main contents includes: (1) In the research of pattern and process, different landscape types can be divided into two kinds of landscape, “source” landscape and “sink” landscape. “Source” landscape is a landscape type which contributes positively to the development of the ecological process, while a “sink” landscape is one which is unhelpful to the development of the ecological process. (2) “Source” landscape and “sink” landscape are recognized with regard to the special ecological process. If
the studied ecological process were changed, “source” landscape could become “sink” landscape. Therefore, the ecological process should be clarified before “source” or “sink” landscape were defined. (3) The key point to distinguish “source” landscape from “sink” landscape is to identify the effect of landscape on ecological process. The positive effect is made by “source” landscape, and the negative effect is made by “sink” landscape. (4) For the same ecological process, different “source” landscapes have different positive effects, and different “sink” landscapes have different negative effects. It is required to determine the weight of different landscape types on ecological processes. (5) Source-sink principle could be applied to non-point source pollution control, biologic diversity protection, heat island effect of city, and so on. For the different study area, the landscape evaluation models need be built respectively, because different ecological process is corresponding with different source-sink landscape and evaluation model.The source-sink principle will be helpful for the further study of landscape pattern and ecological process, and can give a base for designing landscape indices.