A flexible pixel array substrate includes a flexible base, at least one first driving transistor, at least one second driving transistor and at least one pixel electrode. The first driving transistor is disposed on the flexible base and has a first current channel. The second driving transistor is disposed on the flexible base and has a second current channel. The first current channel is not parallel to the second current channel. The pixel electrode is disposed on the flexible base. The pixel electrode is electrically connected to first driving transistor. The pixel electrode is electrically connected to the second driving transistor. In addition, a flexible display applying the flexible pixel array substrate is also provided. Besides, another flexible pixel array substrate and another flexible display applying the same are also provided.