A robust super-hydrophobic coating was constructed on the surface of urea-formaldehyde (UF) foams through a facile immersion process in SiO2 nanoparticle-dispersed ethanol solution with dodecyltrimethoxysilane (DTMS) as compatibilizer. It was found that by introduction of DTMS, strong hydrogen bonding interaction formed between SiO2 coating and UF foam. The UF-g-SiO2/DTMS foam showed a water contact angle (CA) as high as 157.2° and a sliding angle (SA) as low as 3°, and after long-term immersion, very slight change of CA and SA was observed, while the water absorption ratio was only about 12.24%, which was 36.89% and 42.81% lower than that of the pristine UF and UF-g-SiO2 foams, respectively, displaying durable super-hydrophobicity of the foam surface. In addition, the UF-g-SiO2/DTMS foam showed excellent self-cleaning ability. Introduction of DTMS could improve the dispersion of SiO2 in solution effectively and thus lots of bamboo shoot-shaped granular protrusions of SiO2 nanoparticles at micro/nano-scale uniformly formed on the foam surface during treatment process, while the strong interfacial interaction in UF-g-SiO2/DTMS system prevented SiO2 nanoparticles from falling off the foam after long term immersion, which was beneficial for reducing the solid–water contact area, and thus durable hydrophobicity was achieved. The present work showed promising potential for developing high performance UF foam with low water absorption and contamination-free surface on an industrial scale.