Reforestation is one of the most important ways to reduce erosion soil. The objective of this study was to determine the effect of jellyfish soil amendment on seedling growth for reforestation. 100g jellyfish soil amendment was applied into planting hole for the purpose of improvement of the Chamaecyparis obtusa seedling growth. Results showed that during growing period, mortality were 4.4% for the fertilized group and 8.3% for control group. The seedling average height and root diameter were 95.0 cm and 1.07 cm in fertilized group and 40.6 cm and 0.74 cm in control group. The fertilized group was found to be superior (by 1 to 5%) to control group in terms of mortality rate, seedlings height, and root diameter. The positive growth of the fertilized group can be due the increase in soil moisture and the higher availability of nutrients to the plants from jellyfish fertilizer.