A diaphragm is disclosed in the present disclosure. The diaphragm includes a middle layer, a first and a second adhesive layer attached on two side surfaces of the middle layer respectively, and a first layer adhered to the middle layer by the first adhesive layer and a second layer adhered to the middle layer by the second adhesive layer. The first adhesive layer is made of acrylic adhesive and the second adhesive layer is made of silica gel. A speaker using the diaphragm described above is also disclosed. The diaphragm can be used in a relatively wide temperature range and has a strong adaptability to the environment.