A protecting and supporting device for an electronic tablet device includes: slideways (2) provided on a left and a right side of the electronic tablet device (1) and a protection housing (3). Sliding rails (4) are provided on both a left side and a right side of the protection housing (3); wherein two slideways are provided between two sliding rails, the left slideway is slidably connected to the sliding rail on the right side of the protection housing by a sliding shaft (5), the right slideway is slidably connected to the sliding rail on the right side of the protection housing by the other sliding shaft, each sliding shaft can slide in the slideway and the sliding rail on the same side; the slideway and the sliding rail on the same side can rotate relative to the sliding shaft on the same side.