Abstract: A computer-based pattern recognition system has been developed for geological interpretation of Acoustic Sea-bed Profiling Records.Based on practical experience accumulated by specialists,the main pattern characteristics of ASPRs corresponding to typical geological categories of marine sediment layers in the area of the East China Sea have been expressed altogether in 9 aspects,and a dynamic reasoning expert system designed correspondingly.Starting from an initial premise characteristic of the ASPR being interpreted and following a defined'context-tree'including 18 reasoning rules,the expert system successively collects the next premise characteristic and makes the next step reasoning until the final conclusion (i.e.which geological category the sediment layer belongs to.) is derived,in the mean time,for quantitatively estimating the correctness of the final conclusion,the so-called certainty factor is calculated.