Abstract: There was clear standard for classification of structural elements in two basin types both depression and fault depression.However,it was insufficient due to division of structural elements in small sedimentary basins was showed multiple gradation,confusion with second-level of structural elements and variety of nomenclature.Therefore,a proposal reducing gradation and naming second-class structural belt according to their forming mechanism in small sedimentary basin was put forward for the convenience of work.Avoiding a structural element with various names or same name for many structural elements,difference between region and belt must be paid attention to.It was suggested that the names of sag belt,fault depression region and synclinal region etc would no longer to be used.