Abstract: There are always fragment errors in complex structural CAD model,which is prone to bringing troubles into the successive machining operations.To solve this problem,an automatic fragment face error recognition and correction technique based on attribute adjacency graph is proposed.First,the characteristics of fragment face error in complex structural model are analyzed and the definition of the fragment face.error is given.Second,the attribute adjacency graph of the structural part model is constructed.And the attributes of the faces and edges of the graph are calculated to assign the values to elements of the graph.Next,the fragment face error is identified in the form of extended attribute adjacency graph.Then,the relative basic surface of fragment face error is constructed based on its geometric type and parameters.And the basic surfaces are fit to correct the errors.Finally,the algorithm flow of this technique is given and implemented.The experimental results are showed to prove that the presented method is both correct and effective.