A cellulose-silicon oxide composite superhydrophobic material and a preparation method thereof are disclosed. In the method, cellulose substrates with different surface topographies are pretreated by a low-temperature plasma, and then a first silicon oxide layer is deposited on the cellulose substrate by a low-temperature plasma-enhanced chemical vapor deposition method, then modified by a low-temperature plasma, and finally a second silicon oxide layer is deposited thereon, thereby preparing a micro-nano structured superhydrophobic surface on the cellulose substrate, to obtain a cellulose-silicon oxide composite superhydrophobic material, which is an environmentally friendly bio-based hydrophobic material.