An injection molding method for a product with a connection elastic sheet, a loudspeaker and an electronic device are provided. The method comprises: providing a blank material comprising at least one connection piece and a material connection strip, and each connection piece comprising an elastic arm portion and a wire portion; positioning the blank material as an insert in a first injection mold by means of the material connection strip; injecting a first injection plastic part into the first injection cavity to obtain a first injection product; processing the first injection product for bending up the elastic arm portion toward an outer surface of the first injection plastic part; placing the processed first injection product into a second injection cavity of a second injection mold, and sealing the elastic arm portion; and injecting a second injection plastic part into the second injection cavity.