A tablet computer protective case with a keyboard includes an outer cover, an inner cover, a zipper, a partition, and two elastic members. When in use, the protective case is placed on a support plane and the zipper is unzipped to open the inner and outer covers. The keyboard is placed in an inner bottom concave cover of the inner cover, and the tablet computer is placed in an inner top concave cover of the inner cover. After that, a third upper support portion of the inner top concave cover of the inner cover is folded outward relative to a third lower support portion. The first upper support portion of the outer top concave cover of the outer cover is also folded outward relative to a first lower support portion. A second upper support portion of the partition is folded outward relative to a second lower support portion. One side of the outer top concave cover of the outer cover, away from the outer bottom concave cover, leans against the support plane and is supported by the two elastic members, so that the tablet computer and the keyboard form an obtuse angle for the user to use the keyboard and the tablet computer conveniently.