The present disclosure provides a flexible organic light-emitting diode (OLED) display panel including a flexible substrate and a plurality of thin film transistor (TFT) devices disposed on the flexible substrate. The flexible substrate comprises: a first polyimide (PI) layer; a first inorganic barrier layer disposed on a surface of the first PI layer; a titanium metal layer disposed on a surface of the first inorganic barrier layer; a second PI layer disposed on a surface of the titanium metal layer; and a second inorganic barrier layer disposed on a surface of the second PI layer. The TFT devices are disposed on a surface of the second inorganic barrier layer.