A case with assembly structure includes a body, an engaging portion, a fixing element and an elastic element. The body has an accommodating slot and the engaging portion is disposed in the accommodating slot. The fixing element is slidably disposed on the main body and is located on one side of the accommodation slot and adjacent to the engaging portion. The fixing element has a hook. One end of the elastic element is disposed to the body and another end is disposed to the fixing element. The fixing element is moved between a fixed position and a release position along a first direction. When the fixing element is moved to the release position, the hook of the fixing element is moved along a second direction to hook the engaging portion. Meanwhile, the elastic element is made the fixing element be pulled toward the fixed position.