OIL-RESERVING PISTON RING

An oil-reserving piston ring includes an upper wedge ring (100a,200a) and a lower wedge ring (100b,200b) jointed with each other. The upper wedge ring (100a,200a) and the lower wedge ring (100b,200b) are each arranged with an opening, the upper wedge ring (100a,200a) has a first working surface(101,201) contacting with the wall of a cylinder, the lower wedge ring (100b,200b) has a second working surface (102,202) contacting with the wall of the cylinder, and at least one of the first working surface (101,201) and the second working surface(102,202) is arranged with at least one oil-reserving groove (105,106,205,206). Also provided is a piston (600) with only one piston ring slot which is used for arranging the oil-reserving piston ring. The oil-reserving piston ring has a good lubricating property and seal, and is high in reliability.