The invention discloses a preparation method of a pure titanium surface Ag/Sr co-doped TiO2 porous film. A pure titanium sample and a TiAg alloy target are oppositely put in a magnetron sputtering film plating furnace, and argon is fed to pre-sputter and clean the sample after vacuumizing; then, a source pole and workpiece voltage are switched on to form a TiAg alloy film on the surface of the sample through the argon ion bombardment and the metal ion deposition and dispersion; and an alloyed sample, serving as an anode, is dip in electrolyte, a stainless steel electrolytic cell serves as a cathode, and a direct-current pulse micro-arc oxidation device is adopted to perform the micro-arc oxidation to obtain the Ag/Sr co-doped TiO2 porous film under a certain conditions of current density, duty ratio and direct-current pulse frequency. The film, prepared by the method, is excellent in bonding force, has long-acting antibacterial property and excellent biocompatibility, and is simple in operation, excellent in repeatability, suitable for large-batch production and capable of preparing advanced medical implant bone substitute materials.