The invention relates to a vermicular cast iron, particularly a special high-performance high-nickel austenite vermicular cast iron for piston mounting rings and a preparation method thereof. The vermicular cast iron comprises the following chemical components in percentage by mass: 2.0-4.0% of carbon, 1.0-4.0% of silicon, 0.5-8.0% of manganese, 6.0-17.5% of nickel, 2.0-7.5% of copper, at most 2.5% of chromium, 0.008-0.020% of magnesium, 0.01-0.02% of rare earth, at most 0.1% of sulfur, at most 0.2% of phosphorus, and the balance of iron and inevitable impurities. The vermicular cast iron has favorable impact toughness, wear resistance and thermal fatigue strength. The tensile strength sigma b is greater than or equal to 350 MPa, the elongation percentage delta is greater than or equal to 4.5%. The vermicular cast iron has stable performance and longer service life, and greatly prolongs the service life of the piston mounting ring, thereby prolonging the service life of the piston in the engine. The invention also provides a preparation method of the vermicular cast iron, which is simple in technique and easy to implement.