The work aims to develop a hydrophobic, resilient, and biodegradable pulp fiber-based insulating foam. With pulp fibers as the main raw material, sodium dodecyl sulfate as the foaming agent, polyvinyl alcohol as the cross-linking agent, and cationic polyacrylamide as the binder, the pulp fiber-based foam materials were prepared through a process involving pulping, mixing and foaming, drainage, and drying. To reduce the hygroscopicity of the pulp fiber-based foam, a hydrophobic modification was performed by coating with a polylactic acid/silica layer. The performance tests showed that the pulp fiber-based foam had ultra-low density (0.044 3-0.069 8 g/cm3), high porosity (95.22%-97.04%), low thermal conductivity (0.071 1-0.081 1 W/(m.K)), excellent resilience (resilience up to 91.65% after once compression, 87.77% after ten times of compression). The polylactic acid/silica coating significantly improved the thermal insulation, and hydrophobicity (contact angle 132.3°) of the pulp fiber-based foam. Hydrophobic pulp fiber-based foams can be used in cold chain packaging instead of traditional foams, supporting the sustainable development of the packaging industry.