The present invention relates to a hard coating film and a preparation method thereof, and, more particularly, to a hard coating film having high hardness and excellent properties and a method of preparing the same. The method is advantageous in that a high-hardness hard coating film, which is not easily curled, can be easily prepared. The hard coating film prepared by this method can be usefully used in various fields because it has high hardness, scratch resistance, transparency, durability, light resistance, light transmittance and the like.