An OLED display panel and a preparation method therefor are provided. The OLED display panel includes a substrate, an anode layer, an electron transport layer, and a cathode layer, wherein the anode layer includes an anode and an auxiliary electrode disposed in a same layer, and the auxiliary electrode is disposed in an overlapping area. The auxiliary electrode is provided with a groove, an opening of the groove is disposed toward the cathode layer, and the auxiliary electrode extends through the electron transport layer and is electrically connected with the cathode layer.