A dry etching method includes performing at least two etching steps, and further includes injecting protective gas into an etch chamber for processing between any two successive etching steps, wherein the protective gas generates plasma to neutralize electrons accumulated on a side wall of an etching trench. According to the present disclosure, hydrogen plasma is added in an etching process to remove the electrons accumulated on the side wall of the etching trench so as to reduce the microetching effect in multiple etching. In this way, process stability and reliability of a display substrate are improved.