This paper presents a theoretical study of the evolution of tearing modes in tokamak. plasma. Combining the tearing mode with a 1-D transport code, computer simulations are conducted. The result shows that the transport process plays an important role in the development of the macro-instability. Under the mutual interaction of macro-instability and transport process, the MHD pattern of tokamak presents various space and time structure. That also gives rise to the time and space behavior of other plasma parameters such as temperature and density.