This experiment was conducted to prevent the contamination of parasite egg on vegetables for supporting safety production of leafy vegetables. After the chinese cabbages and soil samples were collected at 5 cities of Gyeonggido during 2007-2008, the existence of parasite egg was surveyed. All collected samples had no parasite egg, so the chinese cabbages produced in Gyeonggi area were assumed parasite egg-free. To examine the characteristics of parasite eggs, the pig roundworms, Ascaris suum, were collected from the intestine of infected pig and the parasite eggs were collected from the uterus of A. suum. The eggs of A. suum developed to embryonated eggs, which can infect humans, in 20℃-30℃, but not 15℃ and 35℃, when cultured at different temperatures. The eggs developed to embryonated eggs after drying for 0-24h when cultured after different drying times. Effect of soakage different salt solution and times showed that the eggs developed to embryonated eggs after soakage at 0-25% salt solution for 0-24h. For eliminating the parasite eggs attached leafy vegetables, it was efficient to soak at salt solution for 5 minutes and washing 5 times with water.