Abstract: The crystallization behavior of n-HA/ PA66 biocomposite at different processing pressures and annealingtemperatures was investigated by XRD and DSC. The result s show that the crystalline intensities of pure PA66 andit s composite decrease with the increase of the annealing temperature. For n-HA/ PA66 composites , the peaks ofα1crystals of PA66 disappear , only those ofα2 crystals exist , and with the increase of injection pressure and annealingtemperature , the crystalline intensity of PA66 decreases. The degree of crystallinity of PA66 in composites increaseswith the increase of the injection pressure ; however , the annealing temperature has no obvious effect s on the crystalline degree. The mechanical properties have a close relationship with the crystallization behavior of the materials.