The natural bridges are classified into 4 types in this paper on the basis of their surrounding rocks (dissoluble rock or indissoluble rock), scale parameters (the height of bridge, the height and span of bridge arch), development characteristics of river valley under the bridge(perennial, seasonal river or enneri), and formation mechanism (at surface or underground). A brief description is also made concerning the types, distribution patterns, scale parameters, characteristics of landscape combination and comparison of typical karst natural bridges discovered in