Abstract: The circular sliding slope is a kind of usual destroying mode in nature.To analyze on the stability of this kind of slope，it is usual that the center coordinates and its radius of a circular arc are determined as the independent values of safety factors to find out the critical slide face.However，since there are many peak values in rock slope，this method can easily optimize the part of slope，but not the whole one.To avoid this flaw，the research uses the fracture plane and exist side of sliding rock-mass，and the height of the sliding arc to determine the independent values of the critical sliding face.Because the three values have its own meaning of engineering in sliding slope，the variation range of the three values can be adjusted according to the project necessity，the geological characteristics and the slope shapes to easily and directly analyze the slope stability.By this way，the global searching is realized，which solves the problems in optimizing the slide slopes with many peak values.

Key words: Slope stability, Circular arc sliding slope, Critical sliding face, Global searchin