The invention relates to the field of magnetic steel production, and particularly relates to a preparation method of neodymium-iron-boron magnet applicable to new energy automobiles. The method comprises the steps that raw materials of 28.25% of praseodymium neodymium metals, 2.75% of dysprosium, 0.98% of boron, 0.3% of niobium, 0.6% of aluminum, 2% of cobalt, 0.2% of copper, 0.25% of terbium, 0.2% of gallium, and 64.47% of pure iron are weighed according to the weight proportions and are mixed evenly, and after the processes of fusion in a vacuum induction swing furnace, copper wheel cooling, reaction in a hydrogen quenching reactor, oxidizing agent adding, stirring, and grinding, the magnetic powder is obtained; then models are made for the magnetic powder according to the sizes of the products, and in an environment of complete seal and low oxygen, after the pressing with a high magnetic field pressing machine, and under a high intensity pressure of 20 Mpa, crude products with densities of 4.4-4.8 g / cm<3> are made; the crude products are put into a vacuum sintering furnace, under a vacuum condition, the crude products are heat preserved under a high temperature of 1020-1045 DEG C for 5 hours and under an intermediate temperature of 850-950 DEG C for 3 hours and under a low temperature of 500-560 DEG C for 5 hours, and the neodymium-iron-boron magnet products are obtained.