This paper deals the synthesis and characterization of Pure Hydroxyapatite (Pure HAp) nanopowderan its nanocomposites. Hydroxyapatite - Zinc (HAp-Zn), Hydroxyapatite - Manganese (HAp-Mn) Hydroxyapatite - Titanium (HAp-Ti) and Hydroxyapatite - reduced Graphene oxide (HAp-rGO). The impact of Zn, Mn, Ti and rGO on the underlying, morphological, antimicrobial property and biocompatibility of hydroxyapatite nanopowders are contemplated. The structural characterization analysed through XRD. Pure HAp, HAp-Ti and HAp-rGO displayed hexagonal structure and fuse of Zn and Mn in the host lattice changed the construction into orthorhombic and rhombohedral. The normal crystallite size goes from 51 nm to 37 nm for different nanocomposites. The consolidation of cations (Zn2+ Mn2+ and Ti4+) and anion (CO3 2- ) diminished the crystallite size. Blended nanocomposites has hexagonal construction though there is hexagonal to orthorhombic progress in HAp-Zn and hexagonal to rhombohedral change in HAp-Mn nanocomposites The presence of functional groups in the samples is investigated utilizing FTIR examination. Surface morphology and compound organizations are examined utilizing Scanning Electron Microscope (SEM) and Energy Dispersive X-beam investigation (EDX) individually. The in-vitro antibacterial exercises and biocompatibility of the combined hydroxyapatite and its nanocomposite are examined utilizing Kirby-Bauer antibacterial testing and MTT assay individually. The outcomes show that Titanium and reduced Graphene Oxide fused hydroxyaptite nanocomposites are more harmful against every bacterial strain and didn't show any harmfulness against living tissues.