A negative pressure wound therapy machine includes a body, a liquid container and a floating backwater valve. The body has a vacuum pump and a port with a vacuum suction hole connected to the vacuum pump. The liquid container has a recessed valve groove and a liquid chamber that communicate with each other. The recessed valve groove is detachably connected with the port of the body, so that the liquid container is joined under the body. The floating backwater valve is movable within the recessed valve groove. When the liquid level is higher than a predetermined position of the liquid container, the floating backwater valve on the liquid abuts the vacuum suction hole. The floating backwater valve movable in the recessed valve tank, when the liquid tank of the liquid container is set higher than a predetermined position, the floating backwater valve on the liquid which abuts the negative pressure suction port.一種負壓傷口治療機包含一機體、一液體容器以及一浮動逆止閥。機體具有一真空泵及一連接埠,連接埠設有一負壓吸入口,其連通至真空泵。液體容器具有相互連通的一液體容置槽及一凹陷閥槽,凹陷閥槽係可拆卸地連接於機體的連接埠,使液體容器接合於機體的下方。浮動逆止閥可活動的位於凹陷閥槽內,當液體容置槽內的液體高於一預定位置時,逆止閥浮於液體上而抵接負壓吸入口。100‧‧‧負壓傷口治療機102‧‧‧機體102b‧‧‧真空泵102c‧‧‧負壓吸入口102d‧‧‧連接埠103‧‧‧電池104‧‧‧液體容器104b‧‧‧排水閥104e‧‧‧排水口104f‧‧‧液體容置槽105‧‧‧液體逆止結構106‧‧‧浮動逆止閥
