The cross-sectional (110) surface of In _0.53Ga _0.47As/InP hetero-structure grown by molecular beam epitaxy on an InP (001) substrate is characterized by the cross-sectional scanning tunneling microscopy (XSTM). The cleaved (110) surface across the interface between the In _0.53Ga _0.47As layer and InP layer is atomically flat but displays slight different image contrast between the two neighbor regions. The scanning tunneling spectroscopy (STS) is used to measure the current/voltage ( I-V) spectra. The I-Vdata of the InGaAs surface and InP (110) surface show the different characteristics. The voltage range of zero-current plateau (apparent band gap) in the I-Vspectrum of InP displays the values close to its energy band gaps whereas the plateau ranges in the spectra of In _0.53Ga _0.47As are by contrast generally 50% larger than the energy band gap of In _0.53Ga _0.47As. The above phenomenon implies the different physical pictures on the tunneling of two surfaces. In the case of InP, the flat band model is feasible since the band edge states existing in the InP (110) surface can prevent the surface from being affected by the tip –induced band bending (TIBB) effect. In contrast, the TIBB effect must be taken into account to explain the I-Vspectra of the In _0.53Ga _0.47As (110) surface. A statistical analysis of the I-Vdata of In _0.53Ga _0.47As reveals that the width of current plateau in the I-Vspectrum is generally between 1.05 eV and 1.20 eV and the current onset points (turn-points) with the plateau for the different spectra are slightly different from each other. We are able to explain quantitatively the above features based on the three-dimensional TIBB model given by Feenstra ( 2003 J. Vac. Sci. Technol. B 212080 ). Our calculation reveals that the parameter of density of surface states (DOSS) is a sensitive parameter responsible for the I-Vfeatures mentioned above. According to an appropriate assignment of the value of DOSS, which is generally taken in the scope of (0.8–3.0) × 10 ¹²(cm ²·eV) ^–1, we well predict both the width and the onset points of the current-plateau. Moreover, the model also reproduces the line-shapes of the I-Vspectra measured on In _0.53Ga _0.47As.