An investigation was performed to reveal the relation between the storage and decomposition of the titter DNA of a Zoysia japonica grassland on Mt. Kwanak. The loss constant k of litters was 0.167. The times required for the decomposition of half, 95% and 99% of accumulated DNA on the grassland floor were 3.8, 16.6 and 27.6, respectively. The amount of DNA which is turned to living organism in the ecosystem is higher than that of crude protein. In the case of crude protein, the decay constant k was 0.181. The times needed for the decomposition of half, 95% and 99% of accumulated crude protein on the Z. japonica grassland floor were 3.8, 16.6 and 27.6 years, respectively. Key words: Zoysia japonica, Mt. Kwanak, Litter DNA, Crude protein, Decomposition, Accumulation.