This study was conducted to investigate the effect of different ratios of rice straw to swine manure as an earthworm feed on the change of physico-chemical characteristics and earthworm viability during composting, and further to provide the basic information for an efficient vermicomposting using the manure of livestock. Experimental earthworm used in this study was Eisenia foetida and the ratio of swine manure and rice straw was determined to 100:0(SM), 90:10(SRS10), 80:20 (SRS20), 70:30(SRS30) and 60:40(SRS40) on the basis of volume. The results are summarized as follows. Earthworm appeared after 8 week of aging period, and it was possible for the earthworm to survive in all the treatments. C/N ratio was significantly higher (P＜0.05) in the treatments of rice straw mixture (SRS30 and SRS40) than swine manure alone (SM treatment). Appropriate C/N ratio for earthworm survival was the range of 10.43 to 11.16. During the period of aging, pH value and electrolyticconductivity (EC) were the highest in the treatment of swine manure alone. However, as the inclusion of rice straw was increased, pH value and EC showed a decreasing tendency. Appropriate pH value and EC for earthworm survival were 7.7 to 7.8, and 2.72 to 4.59mS/㎝, respectively. The results from this study indicated that mixing swine manure with rice straw more improved more physico-chemical environment for earthworm growth in comparison with swine manure alone, and rice straw showed the sufficient possibility as a bulking agent for an efficient vermicomposting of swine manure.