The present invention relates to a preparation method for porous hydroxyapatite coatings. In particular, it is a method of using suspension plasma spraying to prepare porous hydroxyapatite coatings, which belongs to the technical field of biomedical material preparations. The present invention added a pore-forming agent into the hydroxyapatite suspension with a solid content of 16%-45%. After full stirring, the feedstock materials for plasma spraying were transferred into the injection system, and injected into the high temperature area of the central plasma flame. Then, the feedstock materials made the heat exchange with the high plasma flame of plasma spraying gun. Then the sprayed raw materials were subjected to breakup and refinement of the droplets, solvent evaporation, the decomposition and gasification of the pore-forming agent and melting of feedstock materials. Finally, the porous hydroxyapatite coatings are directly deposited onto the substrate surfaces of the biomedical materials.