Embodiments of the application provide a brightness compensating method and a self-illuminating display device. The brightness compensating method includes: retrieving a table of compensation parameters pre-stored in the self-illuminating display device, which includes compensation parameters of the N zones, where a compensation parameter of a zone at higher temperature than the temperature in the reference zone is smaller than G, and a compensation parameter of a zone at lower temperature than the temperature in the reference zone is larger than G; and compensating for the brightness of an image displayed in each of the N zones according to the compensation parameters. The embodiments of the application can be applicable to compensation for the brightness of the self-illuminating display device.