Abstract: Based on the principles of restoration ecology and similarity,all species of successional stages in the natural restoration process of degraded karst forests were divided into five groups of adaptation grade.The successional sere was reconstructed according to the community similarity and six stages were defined.The pattern of species group replacement was obtained from observing the changes of adaptive grade species in every sucessional stages.Three evaluation indices such as restoration potential degree,restoration degree and restoration speed were proposed to evaluate the natural restoration process of degraded karst forests.According to the principles discussed above,one GIS based ecological simulation system of degraded karst forests in the natural restoration process was constructed,and applied to the study of the process of natural restoration.