A preparation method of a garment with automatic opening is characterized by comprising the following steps: S1. preparing a garment opening preform: the garment opening preform comprises: functional layers, each layer having a predetermined shape and size, made of hydrophilic material or hydrophobic material; a positioning layer having an inner side, and one or more of the functional layers are connected to a part of the inner side; the first connecting layer is arranged between the positioning layer and the functional layers and is used for connecting the functional layers and the positioning layer; the second connecting layer is connected at least to a part of the inner side of the area where the functional layers are not connected; the adhesive layer is connected to the side of the functional layers far away from the positioning layer. S2. the garment opening preform is used to prepare the garment with automatic opening: the garment opening preform is fixed on the fabric layer of the garment to be opened through the second connecting layer, the fabric layer, the adhesive layer and the functional layers are combined into a composite body, and the composite body is carved and opened to make the fabric layer have a penetrating incision stitch; Removing the positioning layer, the second connecting layer and the first connecting layer, and obtaining the product; the number of incision stitch is the same as that of the functional layers, the shape of incision stitch is the same as that of one side or two interconnected sides of the functional layers, and the opening positions of incision stitch correspond to the distribution positions of the sides of the functional layers. S1. preparing a garment opening preform: the garment opening preform comprises: functional layers, each layer having a predetermined shape and size, made of hydrophilic material or hydrophobic material; a positioning layer having an inner side, and one or more of the functional layers are connected to a part of the inner side; the first connecting layer is arranged between the positioning layer and the functional layers and is used for connecting the functional layers and the positioning layer; the second connecting layer is connected at least to a part of the inner side of the area where the functional layers are not connected; the adhesive layer is connected to the side of the functional layers far away from the positioning layer. functional layers, each layer having a predetermined shape and size, made of hydrophilic material or hydrophobic material; a positioning layer having an inner side, and one or more of the functional layers are connected to a part of the inner side; the first connecting layer is arranged between the positioning layer and the functional layers and is used for connecting the functional layers and the positioning layer; the second connecting layer is connected at least to a part of the inner side of the area where the functional layers are not connected; the adhesive layer is connected to the side of the functional layers far away from the positioning layer. S2. the garment opening preform is used to prepare the garment with automatic opening: the garment opening preform is fixed on the fabric layer of the garment to be opened through the second connecting layer, the fabric layer, the adhesive layer and the functional layers are combined into a composite body, and the composite body is carved and opened to make the fabric layer have a penetrating incision stitch; Removing the positioning layer, the second connecting layer and the first connecting layer, and obtaining the product; the number of incision stitch is the same as that of the functional layers, the shape of incision stitch is the same as that of one side or two interconnected sides of the functional layers, and the opening positions of incision stitch correspond to the distribution positions of the sides of the functional layers. the garment opening preform is fixed on the fabric layer of the garment to be opened through the second connecting layer, the fabric layer, the adhesive layer and the functional layers are combined into a composite body, and the composite body is carved and opened to make the fabric layer have a penetrating incision stitch; Removing the positioning layer, the second connecting layer and the first connecting layer, and obtaining the product; the number of incision stitch is the same as that of the functional layers, the shape of incision stitch is the same as that of one side or two interconnected sides of the functional layers, and the opening positions of incision stitch correspond to the distribution positions of the sides of the functional layers.