The invention provides a TiAl coating capable of achieving heat growth of an aluminum oxide film and a preparing method of the TiAl coating, and belongs to the technical field of coatings. The TiAl coating can be used for high-temperature oxidation protection of a titanium alloy, a titanium aluminum intermetallic compound and other materials. According to the TiAl coating with the selective aluminum oxide film forming capability, the Al atom ratio content of a TiAl alloy target material ranges from 38%-58%. TiAl serves as a target material, in the physical vapor deposition process, a trace of carbon or nitrogen is doped, the TiAl coating with the selective aluminum oxide film forming capability is obtained, a new thought and method are provided for designing a titanium alloy and titanium aluminum intermetallic compound anti-oxidation protection coating, the chemical compatibility between the coating and a base body is good, and brittleness is low. Meanwhile, the technology is simple, controllable, environment-friendly, low in cost and suitable for industrial application. Compared with existing related protection coatings, obvious technical advantages are achieved.