The invention relates to a preparation method of a hierarchical-structure thin-wall BN microtube. The preparation method mainly comprises the following steps: putting a boron-containing precursor intoa tube furnace, introducing nitriding reaction gas, carrying out heating to 1000-1200 DEG C, and keeping the temperature for 2 hours or more to obtain a large batch of high-quality one-dimensional boron nitride hierarchical-structure materials. According to the method, a substrate is not needed; the preparation method is simple and effective in process and low in energy consumption and uses cheapand non-toxic raw materials; and the purity of a purified target product is high, which is favorable for batch production of the boron nitride micro-nano hierarchical structure materials.