A new viewpoint is used to understand the generation process of the Hilbert curve. A one-to-one correspondence between the 4-adic expansion of the unit interval and the fractal curve's iterative generating process is established, and an analytical expression of the level-n Hilbert curve is obtained. This expression can take limit and represent the curve with 2-adic series. Although composition of functions this expression can substitute the generator of the Hilbert curve, while it can be proved, using the expression, that the generation of the Hilbert curve depends on how the subsquares are connected rather than the shape of the generator.