An electronic device protective case, comprising at least: a keyboard assembly and a protective case, wherein the protective case comprises: a supporting assembly, a first connecting member, and a first fastening member; one end of the supporting assembly is rotatably connected to the keyboard assembly, the other end of the supporting assembly is rotatably connected to the first connecting member, and the first connecting member is further slidably connected to the first fastening member; and a surface that is of the first fastening member and that is away from the first connecting member is fixedly connected to an electronic device, wherein the supporting assembly comprises: a support member and a second connecting member fixedly connected to the support member; and the second connecting member is rotatably connected to the keyboard assembly, and the support member is rotatably connected to the first connecting member, wherein the second connecting member comprises: a first connecting portion and a second connecting portion fixedly connected to the first connecting portion; and the first connecting portion is rotatably connected to the keyboard assembly, and the second connecting portion is fixedly connected to the support member, wherein the keyboard assembly comprises: a keyboard body and a third connecting portion connected to the keyboard body, and a first mounting hole is disposed on the third connecting portion; and the first connecting portion comprises: a body portion and a first rotating shaft fixedly connected to the body portion, the first rotating shaft is located in the first mounting hole, and the first rotating shaft and the first mounting hole rotatably match each other, wherein the first rotating shaft comprises: a first rotating shaft portion and a second rotating shaft portion fixedly connected to the first rotating shaft portion; a diameter of the second rotating shaft portion is greater than a diameter of the first rotating shaft portion, and one end that is of the second rotating shaft portion and that is away from the first rotating shaft portion is fixedly connected to the body portion; the first mounting hole comprises: a first sub-mounting hole and a second sub-mounting hole connected to the first sub-mounting hole; and an inner diameter of the second sub-mounting hole is greater than an inner diameter of the first sub-mounting hole, the first rotating shaft portion matches the first sub-mounting hole, and the second rotating shaft portion matches the second sub-mounting hole. a keyboard assembly and a protective case, wherein the protective case comprises: a supporting assembly, a first connecting member, and a first fastening member; one end of the supporting assembly is rotatably connected to the keyboard assembly, the other end of the supporting assembly is rotatably connected to the first connecting member, and the first connecting member is further slidably connected to the first fastening member; and a surface that is of the first fastening member and that is away from the first connecting member is fixedly connected to an electronic device, wherein the supporting assembly comprises: a support member and a second connecting member fixedly connected to the support member; and the second connecting member is rotatably connected to the keyboard assembly, and the support member is rotatably connected to the first connecting member, wherein the second connecting member comprises: a first connecting portion and a second connecting portion fixedly connected to the first connecting portion; and the first connecting portion is rotatably connected to the keyboard assembly, and the second connecting portion is fixedly connected to the support member, wherein the keyboard assembly comprises: a keyboard body and a third connecting portion connected to the keyboard body, and a first mounting hole is disposed on the third connecting portion; and the first connecting portion comprises: a body portion and a first rotating shaft fixedly connected to the body portion, the first rotating shaft is located in the first mounting hole, and the first rotating shaft and the first mounting hole rotatably match each other, wherein the first rotating shaft comprises: a first rotating shaft portion and a second rotating shaft portion fixedly connected to the first rotating shaft portion; a diameter of the second rotating shaft portion is greater than a diameter of the first rotating shaft portion, and one end that is of the second rotating shaft portion and that is away from the first rotating shaft portion is fixedly connected to the body portion; the first mounting hole comprises: a first sub-mounting hole and a second sub-mounting hole connected to the first sub-mounting hole; and an inner diameter of the second sub-mounting hole is greater than an inner diameter of the first sub-mounting hole, the first rotating shaft portion matches the first sub-mounting hole, and the second rotating shaft portion matches the second sub-mounting hole.