In this study, calcium phosphate-chitosan nanocomposite (CaP-CS NC) was prepared by a convenient and affordable co-precipitation method, and the prepared NC was tested for agriculture application.  Physico-chemicals analyses of the CaP-CS NC were conducted by X-ray diffraction (XRD), scanning electron microscope with energy dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), and ultraviolet-visible spectroscopy (UV-Vis) instruments to determine the structural characteristics, surface topology, chemical composition, function group, and optical properties. The XRD pattern of CaP-CS NC revealed that the average crystallite size was 43 nm. The SEM images showed agglomeration of the CaP-CS NC with a rod-like shape. The EDS spectrum of the CaP-CS NC indicated the presence of Ca, P, O, and N elements. FTIR displayed vibrational peaks for the active functional group such as carboxylic (C=O), amines (N-H), hydroxyl (O-H), and alkyne (C-H). Furthermore, the spectrum of CaP-CS NC showed the bending mode of phosphates at 588.37 cm-1 and 508.45 cm-1. The UV-Vis-NIR spectrum of the prepared nanocomposite indicates the anti-reflection properties, which might be useful in solar cell applications to increase the efficiency of the solar cell. In addition, the prepared CaP-CS NC was tested for the plant growth stimulator properties at the lab scale level, wherein it exhibited substantial growth. Accordingly, the current study suggests that the prepared CaP-CS NC could be used as a plant growth promoter.