In Interactive cognitive radio networks (ICRN), secondary usage of spectrum is of competition and con°ict, and radio frequency environment is time-varying. In order to realize real-time secondary spectrum usage, we propose architecture based on SoftMan for the ICRN. In this architecture, the ICRN are divided into many coali- tions according to geographical locations, utilization de- gree of spectrum, frequency range and transmission power level. In one coalition, a dynamic spectrum management model based on di®erential games is proposed, and feed- back Nash equilibrium solution to the non-cooperative dif- ferential games is given and analyzed. Di®erential games study a class of decision problems, under which the evolu- tion of the state is described by a di®erential equation and the players act throughout a time interval. So the model can ensure real-time secondary spectrum usage. The simu- lation results show that the model can improve e±ciency of spectrum utilization, and re°ect realistically time-varying radio frequency environment. It also constitutes the theo- retical foundation for the spectrum management in a dy- namic environment.