A new improved transfer matrix method (TMM) is presented. It is shown that the method not only overcomes the numerical instability found in the original TMM, but also greatly improves the scalability of computation. The new improved TMM has no extra cost of computing time as the length of homogeneous scattering region becomes large. The comparison between the scattering matrix method(SMM) and our new TMM is given. It clearly shows that our new method is much faster than SMM. Transfer matrix method (TMM) has been a useful approach for studying the physical properties. There have been many publications on application of the TMM, such as studies of Ising model [1,2,3,4], quantum spin [5], electronic transport [6,7], and electronic state in quasiperiodic and aperiodic chains [8,9]. TMM is also widely applied in studying the propagation of electric-magnetic wave [10], elastic wave [11] and light wave [12] in multilayer systems.