The invention discloses a one-way valve comprising a valve body, a valve core and a spring. A valve chamber is defined inside the valve body. The valve body is provided with an air inlet channel and an air outlet channel. The valve core is movable disposed inside the valve chamber, and is unidirectionally connected to the valve chamber in the direction from the air inlet channel to the air outlet channel. The valve core is a medical silica gel element. The two ends of the spring respectively abut against the valve core and the valve body so as to drive the valve core to enclose the air inlet channel under a state that the one-way valve is not ventilated. According to the invention, the valve core is the medical silica gel element, so that the one-way valve has high requirements on bio-compatibility, and the one-way valve can be applied to a gas path system of a medical apparatus. The valve core is made of soft and light materials, so that vibration can be avoided under the cooperation of the valve core and the spring having a suitable elastic force, and noise does not occur when the one-way valve normally work in the gas path system.