The search for Majorana bound state (MBS) has recently emerged as one of most active research areas in condensed matter physics, due to its non-Abelian statistics which can be used for robust quantum computation.  Currently, most experimental platforms for searching for MBS usethe idea of topological insulator in proximity to BCS superconductor or similar ideas. Recently we discovered a new platform of Fe-based superconductor Fe(Te,Se) single crystal. By using spin-resolvedand angle-resolved photoelectron spectroscopy, we observe that the iron-based superconductor FeTe1-xSex (x = 0.45, Tc = 14.5 K) hosts Dirac-cone type spin-helical surface states at Fermi level, which open an s-wave SC gap below Tc.By using scanning tunneling microscope on the same material, we clearly observe a pristine MBS inside a vortex core, well separated from non-topological bound states. These observations offer a robust platform for realizing and manipulating Majorana bound states at a relatively high temperature.