Provided are a biodegradable fiber-reinforced super-hydrophobic friction material and a preparation method thereof. The material is prepared from, by weight, 21-27% of biodegradable corn straw fiber and Lapinus fiber, 8-15% of super-hydrophobic pine shell and cotton straw mixed powder, 8-11.5% of polyvinyl alcohol modified phenolic resin, 5-8.5% of crystalline potassium titanate, 0-12% of crystalline flake graphite, 6-30% of wollastonite, 1-8% of brown fused alumina, 8-20% of silicon carbide, 10-28% of foam iron powder and 3-10% of vermiculite powder. The problem that single fiber strength is weaker can be effectively solved through collaborative design of biodegradable corn straw fiber and Lapinus fiber, braking noise is reduced, and the scratching of the friction material to a pair is decreased. The overall performance of the friction material is improved, friction factors are stabilized, and the abrasion quantity is decreased, so that the friction material has reasonable service life, compression amount and good heat-conducting performance, has very good weather resistance, the influence of rainwater, ice and snow on the friction material can be very well prevented, and the reliability of the friction material is improved.