Sub-display panel assembly and tiled display device

A sub-display panel assembly comprises: at least one display substrate (6); a base plate (1) having a first surface (1a); the base plate fixing structure comprises a lifting assembly (2), a connecting assembly (3) and a supporting assembly (4), the lifting assembly (2) is located in the bottom plate (1), the supporting assembly (4) is located on one side of the first surface (1a) of the bottom plate (1), the lifting assembly (2) is connected with the supporting assembly (4) through the connecting assembly (3), the lifting assembly (2) and the connecting assembly (3) are detachably fixed, and the supporting assembly (4) is located on one side of the first surface (1a) of the bottom plate (1). The supporting assembly (4) is configured to support the display panel (6), and the lifting assembly (2) is configured to move in the normal direction of the first surface (1a) and drive the connecting assembly (3) and the supporting assembly (4) to correspondingly move in the normal direction of the first surface (1a). The invention further provides a tiled display device.