The work aims to improve the buffer properties and hydrophobicity of plant fiber foams and investigate the effects of modification of natural latex on foam properties. With natural latex (NRL) and plant fiber as matrix, polyether (F127) as blowing agent and polyvinyl alcohol (PVA) as plasticizer, a new NRL modified plant fiber foam composite was prepared by mechanical foaming method. The effects of the amount of NRL on the microstructure, water contact angle, compression properties, thermal insulation and thermal stability of the foam composites were studied. The plant fiber foam with a mass ratio of NRL/PVA=2∶1 had the best comprehensive properties, the hydrophobic angle was up to 121.4°, the compressive strength (80% strain) was 1 102.8 kPa, the resilience (50% strain and 10 cycles) was up to 76.38%, and the static buffer coefficient was as low as 0.04. After heating at 80 ℃ for 60 min, the surface temperature only increased by 5 ℃. In summary, the plant fiber foam material modified by NRL has good functions of hydrophobicity, buffer and heat insulation.