As the demands of environment protection increases, the pulp mold container is developed to substitute for EPS (expanded polystyrene) as a shock absorbing packaging material. The water-absorbing ratio and mechanical properties such as tensile strength and compressive strength of pulp mold are important factors to evaluate its shock absorbing characteristics. Influences of mixing ratios of ONP (old newspaper) and OCC (old corrugated container) on physical properties of pulp mold were investigated at various conditions of temperature and relative humidity. The optimum mixing ratio of ONP and OCC was also searched based on physical properties. The results showed that when relative humidity was increased from 60% to 90%, the water absorption ratio of pulp mold increased significantly, tensile strength decreased 20$sim$30%, and compressive strength decreased 10$sim$20%. In addition, the optimum mixing ratio of ONP and OCC was found to be 50%:50%.