The invention relates to the field of organic fiber and its preparation, in particular to a preparation method of aramid pulp. The preparation method comprises the main steps that aramid fiber is sequentially subjected to corona treatment, humidification treatment, high-speed rotary pulverizer dry-method pulping and other technological processes. The method is short in technological process, low in energy consumption and harmless to the environment and does not adopt solvents and other organic materials, the obtained product is pure and free of impurity contaminations, the average length of the aramid pulp is 0.5-1.5 mm, the specific surface area is 5-12 g/m<2>, the fibrillation degree is high, hairiness is rich, and the preparation method is suitable for the fields such as sealing materials.