The synthesis of hydroxyapatite (HA) has been widely studied in the field of biomaterials, due to its structural similarity with the biological bone apatite. This biomaterial guarantees implants with high bioactivity and osteoconductivity properties and consequently is successfully used as osseous tissue substitute. It has been reported that some ions have a positive influence on the HA solubility and therefore on its biological activity as a result of the change in the crystal lattice. In this work, nanoparticles of HA were obtained by the method of wet precipitation ultrasound assisted, with the coprecipitation of some metallic ions (Sr2+, Mg2+ and Li+). Concentrations used was 10% molar (Sr2+), (Mg2+) and (Li+) on HA single doped, while samples with double doped of Sr2+/Mg2+ and Sr2+/Li+ were synthesized in proportions of 25 % molar of substitutions degree. The synthesized particles were studied using XRD, FTIR, DLS and XPS techniques. The results showed that the chemical substitutions occurred in the crystal lattice with an influence on the parameters of network and the decrease of HA crystallinity. All samples of HA had nanometric dimensions: crystallite sizes were in the range of 30-46 nm, while particle sizes were between 190-300 nm. The FTIR and DRX analyzes confirmed the obtaining of pure phases. The XPS analysis also indicated the presence of metallic ions in the HA.