A detailed study of the mechanical properties of luffa sponge, a natural plant fiber material, was carried out to explore its potential to be applied to the elastic filling material of sofa cushions, as well as its collapse and support performance in practical applications. Combined with actual use scenarios, it simulates people using the sofa at short intervals and the situation after many years of use, and conducts strain relaxation and durability test design. After the high-density luffa sponge was compressed, it has a certain degree of elasticity, and it may be applied to cushion elastic materials. The high-density luffa sponge had good resilience and could basically rebound to the original height after 6h; the high-density luffa sponge had better overall creep resistance, and the high-density luffa sponge had the smallest creep degree when compressed 20% of its height. And after simulating the long-term repeated loading and unloading durability test, there was no overall collapse or deformation. It further proves the potential of luffa sponge to become a substitute of biomass foam material for sponge in sofa cushions.