Airborne lidar (LIght Detection And Ranging) system has been proved cost effective for surveying near shore shallow water, where complicate and dangerous underwater environments prohibit the shipborne sonar survey. Such an area is usually of great importance for environmental management and natural resources inventory. Current algorithms for locating edge points assume the earth's surface is continuous in all directions and differ in how they measure discontinuities between surfaces from the bare earth. In this paper, the signal of the airborne bathymetric lidar system, which is affected by the reflectance of the bottom materials, is used to detect the change of the ocean bottom. We propose a procedure based on Kriging method and the difference of the kriging predicted value and original value to find edge points. A dataset of Egmont Key, FL, collected by SHOALS, is tested. Our results show that the procedure can produce consistent results of edge point locations.