The invention relates to a method for preparing composite hydrophobic nano powder-coated liquid marbles, which belongs to the technical field of coating materials. The invention uses nano-zinc oxide powder, nano-titanium dioxide powder and nano-alumina powder as raw materials to prepare a composite hydrophobic nano-powder that wraps liquid, and can effectively reduce the liquid in the marble by wrapping the hydrophobic nano-zinc oxide powder. The risk of harmful bacterial contamination, thereby improving the safety of liquid marbles, nano-titanium dioxide has a strong UV shielding effect, and is effective against Bacillus subtilis var. niger, Pseudomonas aeruginosa, E. The extinction rate reaches 98~99%, which can effectively improve the medical use and safety of liquid marbles. Nano-alumina is in the state of white fluffy powder, which has the advantages of large specific surface area, high porosity, strong adsorption and good formability. It can effectively adsorb on the surface of the liquid, and effectively adsorb and bond other particles on the surface of the liquid, thus forming a stable liquid marble.