The invention relates to a method for launching and floating of a ship carrying chamber of a ship lift, and belongs to the field of navigation structures of water conservancy and hydropower engineering. A launching type ship lift ship chamber is located in a reservoir, the ship chamber and the lower portion structure of an upper gate bay are submerged under water, under the normal operation condition of the reservoir, the ship lift does not meet the requirement of unwatering the ship chamber, so that the ship carrying chamber can only adopt integral floating. In order to let the ship carrying chamber enter the ship chamber safely and stably in a floating mode, a method which can make the ship carrying chamber enters the ship chamber in a floating mode needs to be designed. The method for launching and floating of the ship carrying chamber of the ship life includes the following steps of prospecting site conditions of the ship lift, understanding the basic information of the ship carrying chamber, building up an organization mechanism of floating of the ship carrying chamber, understanding the basic requirements the ship carrying chamber needs to meet before launching, preparing safety measures before floating, launching the ship carrying chamber, floating and dragging of the ship carrying chamber, and fixing and positioning the ship carrying chamber after entering the ship chamber in a floating mode. The method for launching and floating of the ship carrying chamber of the ship lift is reasonable in design, and considerate.