The life jacket is made of coated fabric, which is formed in one time through high-frequency heat sealing process. It is mainly composed of an automatic inflation device, an air replenishing valve, a safety valve, a whistle, a position indicating lamp, a belt, etc. The belt can be adjusted to suit people of different shapes. After falling into the water, the life jacket is automatically inflated to shape, so that the wearer can float on the water. It is mainly suitable for water operation personnel such as docks and ships.