A touch display device includes a first substrate, a second substrate, a plurality of sub-pixel regions, a plurality of display devices, a plurality of first optical touch sensor device and second optical touch sensor devices. The first substrate and the second substrate are disposed oppositely. The display devices are disposed in the sub-pixel regions, respectively, to provide images for a first display surface and a second display surface. The first optical touch sensor devices are disposed on the first substrate and at least corresponding to part of the sub-pixel regions for implementing touch input function on the first display surface. The second optical touch sensor devices are disposed on the first substrate and at least corresponding to part of the sub-pixel regions for implementing touch input function on the second display surface.