Hydroxyapatite (HAP) urchins were synthesized by a facile hydrothermal method using calcium nitrate, ammonium dihydrogen phosphate, diamine tetraacetic acid disodium salt as complexing agent and ethonalamine as alkaline source. The influence of hydrothermal time on crystallinity and morphology of HAP have been investigated. The results indicate that well-crystallized HAP urchins can be synthesized at 180°C for 24h. SEM images show a large area of urchin-like microspheres consisted of a number of ribbons with lengths ranging from 2 to 5μm. Based on XRD and SEM results, the formation mechanism of HAP crystals has been discussed. A typical anti-inflammatory drug, ibuprofen, was used for drug loading, and the release behaviors of ibuprofen in a simulated body fluid (SBF) were studied. The results indicate that HAP urchins showed a favorable sustained release property for ibuprofen.