The invention discloses a display panel, a preparation method thereof and a mobile terminal. The display panel comprises a substrate, an active layer, a gate insulating layer, a gate metal layer, an interlayer insulating layer and a source-drain metal layer, the display panel further comprises an isolation layer, the active layer comprises a polycrystalline silicon semiconductor sub-layer and a metal oxide semiconductor sub-layer which are arranged on the substrate, the metal oxide semiconductor sub-layer comprises a metal oxide active section and a metal oxide conductor section, and the isolation layer is arranged on the metal oxide conductor section. The orthographic projection of the isolation layer on the substrate at least partially covers the orthographic projection of the metal oxide conductor section on the substrate, on one hand, the display panel film layer is simple in structure, the production cost is reduced, the thickness of the display panel is reduced, and on the other hand, the display panel film layer is convenient to manufacture. Due to the arrangement of the isolation layer, the property of the metal oxide semiconductor sub-layer is not affected by the fact that the metal oxide semiconductor sub-layer and the polycrystalline silicon semiconductor sub-layer are arranged on the same layer.