A display substrate and a method of preparing the same, and a display device are provided, the method including: providing a substrate; forming a switching thin film transistor precursor and a driving thin film transistor precursor on the substrate, each including a semiconductor layer, a gate insulating material layer and a gate metallic layer stacked sequentially above the substrate; forming a photoresist layer above the switching thin film transistor precursor and the driving thin film transistor precursor, and forming an etching mask from the photoresist layer, a first portion of the etching mask at the switching thin film transistor precursor and a second portion of the etching mask at the driving thin film transistor precursor having different shapes; and forming a switching thin film transistor and a driving thin film transistor, by etching processing the switching thin film transistor precursor and the driving thin film transistor precursor with the etching mask.