This thesis covers the design of microprocessor using structural C. Structural C is the subset of C language for designing microprocessor. It is much faster than HDL, so testing and simulation time can be reduced. In designing microprocessor simulation time is very critical, so structural C is indispensable. The differences between HDL and structural C and the way to describe a microprocessor in structural C are covered in this thesis. Also as an example, the designing of control unit and execution unit of K486, which is compatible with i486, is covered.