The milk powder was dissolved in ultrapure water, and the inorganics-rich components in the milk powder were extracted after ultrasonication, centrifugation and vacuum freeze-drying, and the inorganics-rich components in the milk powder were qualitatively analyzed by X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy. In addition, different concentrations of needle-like nano-hydroxyapatite reference standard were added to the blank milk powder sample, and the same prelimina-ry treatment and analysis as the milk powder samples was carried out. The morphology and nano-size of the inorganics-rich components in sample 1 and spiked sample were characterized by scanning electron microscopy (SEM) and transmission electron microscopy connected with energy spectrometer (TEM-EDS). The results showed that the spiked samples were determined to contain hydroxyapatite component in the XRD test. The needle-like nano-hydroxyapatite can be observed under electron microscope, thus verifying the feasibility of this method for detecting nano-hydroxyapatite. Among five samples, one sample contained hydroxyapatite in the XRD test and a spherical nano-component with unknown structure (the element composition was C, O, P, Cl); while three samples contained crystalline calcite and one sample did not contained crystalline hydroxyapatite.