Abstract: There are geological wonders of level chessboard bedrock stones of which the development size is 0.25~3.00 m2 and the area is 15 600 m2 on Naba riverbed of Naba town of Guangxi Tiandong. Based on surveying the national conditions, such as stratum, lithology, geologic structure, landform and the topographic features in the deve-lopment area, the statistical analysis results show that X-extension joint feature of sandstone under the side force effect is the precondition and base to form the materials. The statistical analysis incudes counting the developing rules of tectonic joint and comparing different river beaches of Naba River around chessboard beach with the same geological base. The special hydrologic condition of the river is the main force forming the chessboard beach; and the horizontal structure and the trumpet riverbed landform are important control factors for forming and storing the chessboard beach.