The　all-electron　full-potential　linearized　augmented　plane-wave　method　has　been　used　for　an　ab　initio　theoretical　study　of　the　band　structure,　the　spectral　I　features　of　the　optical　susceptibilities,　the　density　of　states,　and　the　electron　charge　density　for　PbBiBO4.　Our　calculations　show　that　the　valence-band　maximum　(VBM)　and　conduction-band　minimum　(CBM)　are　located　at　the　center　of　the　Brillouin　zone,　resulting　in　a　direct　energy　gap　of　about　3.2　eV.　We　have　synthesized　the　PbBiBO4　crystal　by　employing　a　conventional　solid-state　reaction　method.　The　theoretical　calculations　in　this　work　are　based　on　the　structure　built　from　our　measured　atomic　parameters.　We　should　emphasize　that　the　observed　experimental　X-ray　diffraction　(XRD)　pattern　is　in　good　agreement　with　the　theoretical　one,　confirming　that　our　structural　model　is　valid.　Our　calculated　bond　lengths　show　excellent　agreement　with　the　experimental　data.　This　agreement　is　attributed　to,our　use　of　full-potential　calculations.　The　spectral　features　of　the　optical　susceptibilities　show　a　small　positive　uniaxial　anisotropy.