Abstract: In this paper,an intermediate representation that is a hierarchical CDFG called HCDFG-II,and its transformation method are proposed.HCDFG-II,extended from the definition of HCDFG for software/hardware partition,is based on C language system specification.HCDFG-II introduces the memory accessing nodes to deal with the arrays and pointers of C program,and defines the concurrent structure to express the concurrent parts.At the same time,the transformation from C language to HCDFG-II becomes very easy since HCDFG-II adopts a control flow first structure.All these features provide more precise information for software/hardware partition,and make HCDFG-II an effective intermediate representation of C language specification.