Ecological degeneration induced by urban sprawl is one of the most significant components of environmental change in rapidly urbanizing area,and its spatial-temporal complexity makes it analytically challenging to conduct empirical studies. This paper presents a case study in Nan Shan district,Shenzhen,from 1988 to 2003.Motivated by the theoretical insights of self-organizing criticality(SOC)this paper has three objectives:(1) To study the relationship between the process of urban sprawl and ecological degeneration; (2) the assessment of SOC in the processes of ecological degradation process; (3) The dynamic characteristics of ecological degradation. To relate urban sprawl and ecological degradation process,the study area is subdivided into three main categories based on land use types:Forest dominant area(F),Agricultural dominant area(A) and Build-up dominant area(B).We discovered that ecological degradation is composed of three main processes:Forest dominant area converted to Agricultural dominant area(FTA),Agricultural dominant area converted to Build-up dominant area(ATB) and Forest dominant area converted to Build-up dominant area(FTB).According to the size-frequency and “Power Law” distribution,their spatial and temporal fractal characteristics were verified.The following are the main conclusions of this paper:(1) Urban sprawl and three main ecological degradation spatial and dynamic size-frequency distribution follow “Power Law”,these process are all in SOC state.(2) Urban sprawl is the driving force for ecological degeneration aiming three major types of land use; their dynamic fractal indices have the same trend.(3）The increase of the dynamic fractal indices of urban sprawl and ecological degradation indicate the process of transformation from large to small patches.