A protective case, comprising: a main body, wherein an electronic device is installed on the main body; and a fixing strap disposed on the main body for holding an object between the fixing strap and the main body, said fixing strap comprising: a first elastic part connected with an inner surface of the main body, and comprising at least one first opening, wherein an elastic force of the first elastic part is adjustable through the at least one first opening; a second elastic part connected with the inner surface of the main body, and comprising at least one second opening, wherein an elastic force of the second elastic part is adjustable through the at least one second opening; and a connecting part arranged between the first elastic part and the second elastic part and connected with the first elastic part and the second elastic part, wherein when the connecting part is not pulled, the connecting part is accommodated within a hollow portion of the main body and exposed to an outer surface of the main body, and the connecting part is coplanar with the outer surface of the main body, wherein when the connecting part is pulled, the first elastic part and the second elastic part are stretched and subjected to deformation, so that the object is held between the connecting part and the main body, characterized in that the main body further comprises a stopping plate under the hollow portion, wherein two parallel rims of the stopping plate are connected with two corresponding parallel rims of the hollow portion, and two connection holes are respectively located at two opposite sides of the stopping plate. a main body, wherein an electronic device is installed on the main body; and a fixing strap disposed on the main body for holding an object between the fixing strap and the main body, said fixing strap comprising: a first elastic part connected with an inner surface of the main body, and comprising at least one first opening, wherein an elastic force of the first elastic part is adjustable through the at least one first opening; a second elastic part connected with the inner surface of the main body, and comprising at least one second opening, wherein an elastic force of the second elastic part is adjustable through the at least one second opening; and a connecting part arranged between the first elastic part and the second elastic part and connected with the first elastic part and the second elastic part, wherein when the connecting part is not pulled, the connecting part is accommodated within a hollow portion of the main body and exposed to an outer surface of the main body, and the connecting part is coplanar with the outer surface of the main body, wherein when the connecting part is pulled, the first elastic part and the second elastic part are stretched and subjected to deformation, so that the object is held between the connecting part and the main body, a first elastic part connected with an inner surface of the main body, and comprising at least one first opening, wherein an elastic force of the first elastic part is adjustable through the at least one first opening; a second elastic part connected with the inner surface of the main body, and comprising at least one second opening, wherein an elastic force of the second elastic part is adjustable through the at least one second opening; and a connecting part arranged between the first elastic part and the second elastic part and connected with the first elastic part and the second elastic part, wherein when the connecting part is not pulled, the connecting part is accommodated within a hollow portion of the main body and exposed to an outer surface of the main body, and the connecting part is coplanar with the outer surface of the main body, wherein when the connecting part is pulled, the first elastic part and the second elastic part are stretched and subjected to deformation, so that the object is held between the connecting part and the main body,