Regenerated cellulose films and a water-resistant film coated with thin Tung oil were prepared by using a cellulose cuoxam solution from pulps of cotton linter, cotton stalk, and wheat straw. They were buried in the soil to test biodegradability. The results showed that viscosity average molecular weight M(eta), tensile strength sigma(b), and the weight of the degraded films decreased sharply with the progress of degradation time, and the kinetics of decay were discussed. The degradation half-lives t(1/2) of the films in soil at 10-20 degrees C were given to be 30-42 days, and after 2 months the films were decomposed into CO2 and water. The ct-cellulose in soil was more readily biodegraded than hemicellulose, and regenerated cellulose film was more readily biodegraded than kraft paper. Nuclear magnetic resonance and scanning electron micrographs indicated that the biodegradation process of the films was performed through random breakdown of bonds of cellulose macromolecules resulting from the microorganism cleavage.