The invention relates to a lanthanum-doped hydroxyapatite compound coating and a preparation method thereof, and particularly, aims at providing an active coating with high stability in body fluid simulation and a preparation method thereof. The preparation method comprises the steps of: preparing calcium nitrate aqueous solution and ammonium dihydrogen phosphate aqueous solution, controlling pH, adding dropwise and mixing, and then uniformly stirring to obtain electrolyte; preparing a hydroxyapatite coating by means of electrochemical deposition in the case that titanium or titanium alloy matrix is used as anode and platinum sheet is used as cathode; and soaking the hydroxyapatite coating in lanthanum nitrate for a certain period of time, taking out the sample and drying to obtain the lanthanum-doped hydroxyapatite compound coating. The compound coating disclosed by the invention has the characteristics that hydroxyapatite is doped with lanthanum through soaking treatment, thus the stability of the coating in body fluid simulation is improved and the coating is seldom absorbed, as a result, the coating disclosed by the invention is applicable for the repair of various bones.