One-way valve and air conditioner

The utility model discloses a one-way valve and an air conditioner and relates to the technical field of air conditioners. The technical problem that whistler easily occurs in an existing one-way valve is solved. The one-way valve comprises a valve body, a guide pillar, a piston and a retaining component, wherein the guide pillar, the piston and the retaining component are arranged in the valve body, the piston is arranged to be capable of sliding along the guide pillar to form a fluid inlet between the piston and the valve body, the guide pillar is arranged to be fixedly connected to the valve body through the retaining component, the retaining component comprises a center portion and at least two retaining bodies which extend from the center portion and are spaced in the circumferential direction, the retaining bodies are oblique at least partly relative to the center portion, and an opening formed between the retaining bodies allows the fluid entering the valve body through the fluid inlet to flow out of the one-way valve through the opening. The one-way valve and the air conditioner are used for increasing the overflow area of the one-way valve to lower the noise of the one-way valve.