Abstract: Provided are an auxiliary spring, a new-belted diaphragm and an air spring. The air spring comprises an auxiliary spring and a new-belted diaphragm arranged above the auxiliary spring, the auxiliary spring comprises a rim (1), which has a reversed convex structure and has a downward support column on a bottom surface thereof; a rubber piece (2), a center of which has a concave hole for enclosing the whole support column and a top of which contacts with a concave bottom surface of the rim (1); and a base plate (3); the new-belted diaphragm comprises a top cover (41) and a diaphragm body (42) that has a hollow structure and is installed below the top cover (41); a top of the diaphragm body (42) is an annular opening and is connected with the top cover (41), and a middle vertical portion thereof is a girdle portion.