Abstract:   Objectives:   Three dimensional buffer analysis is a spatial analysis function widely used in geographic information systems, which is of great significance in underwater submersible terrain matching navigation, submarine engineering construction planning, submarine pollution source diffusion analysis and other bathymetric research fields. The traditional buffer surface construction algorithm has limitations in the application of TIN-DDM model accuracy and modeling efficiency. Therefore, taking the rolling ball acceleration optimization model with controllable accuracy threshold as the analysis object, this paper proposes a fast TIN-DDM buffer surface construction algorithm based on the efficient determination of key sampling points.   Methods:   Main research contents: (1) Based on the spatial distribution characteristic analysis of alternative point sets, through the numerical convergence analysis of the critical rolling ball radius, the trial iteration strategy of critical rolling sphere radius is designed, then a new criterion for determining key sampling points is given. (2) the spatial data block index modeling is applied to the rapid positioning of adjacent alternative points, and an efficient judgment model of key sampling points for rapid positioning of spatial index is established.   Results:   From the statistical results of the key data link list parameters and the actual buffer surface construction images, the method in this paper can be used to build the buffer surface, and is consistent with the construction accuracy of the rolling ball accelerated optimization model. From the results of buffer surface construction time consuming of different TIN-DDM water depth data, the time consuming of this method is obviously better than that of the rolling ball accelerated optimization model.   Conclusions:   The experimental results show that in the face of massive TIN-DDM data, algorithm in this paper can effectively improve the construction efficiency of buffer surface on the basis of ensuring the construction accuracy of buffer surface, and reduce the time complexity of overall buffer surface construction to O(2n+nwm/φ(n)).