The interaction between an electron and an elastic wave is investigated for HgTe and InAs-GaSb quantum wells. The well-known Bernevig-Hughes-Zhang model, i.e., the 4 × 4 model for a two-dimensional (2D) topological insulator (TI), is extended to include terms that describe the coupling between the electron and the elastic wave. The influence of this interaction on the transport properties of the 2DTI and of the edge states is discussed. As the electron-like and hole-like carriers interact with the elastic wave differently due to the cubic symmetry of the 2DTI, one may utilize the elastic wave to tune/control the transport property of charge carriers in the 2DTI. The extended 2DTI model also provides the possibility to investigate the backscattering of edge states of a 2DTI more realistically.PACS numbers: 73.21. Fg, 78.20.Ls, 78.30.Fs, 78.67.De When a two-dimensional (2D) topological insulator (TI) has a boundary with a normal insulator or vacuum, it is predicted theoretically that there exist gapless edge states. 1-3 The existence of such edge states have been confirmed experimentally. 4-7 When the system is time reversal invariant, these edge states will not be affected by an elastic back scattering center. 1-3 Thus, one has a transport channel for the charge carriers, i.e., the information carriers, with no energy dissipation, and this will be of great application importance in the information technology.