Atmospheric particulate matters were collected by 8-stage non viable cascade impactor from October 2002 to August at Jeju City. Eight water-soluble ionic components $(Na^+,;NH_{4}_{+},;K^+,;Ca{2+},;Mg^{2+},;CI^-,;NO_{3}^-;and;SO_{4}^{2-})$ were analyzed by Ion Chromatography. The concentration of particulate matters and eight water-soluble ionic components were determined to investigate their size distributions. Particulate matters exhibited a tri-modal distribution with peak value around $0.9,;4.0{mu}m;and;9.5{mu}m.$ In summer, the last peak value was lower than other season values likely due to particulate matter scavenged by rain water. Four ionic components $(Na^+,;Ca^{2+},;Mg^{2+};and;CI^-)$ exhibited a bi-modal distribution in the coarse mode whereas three ionic components $(NH_{4}^+,;K^+;and;SO_{4}^{2-})$ in the fine mode, with maximum peak value around $0.9{mu}m.;NO_{3}^-$ was found in both the coarse and the fine mode. The enrichment factor (E.F.) of each ionic components was calculated. Based upon E.F., it is considered that $Na^+,;CI^-,;and;K^+$ in coarse paricle mode were delivered form oceanic source, but other components might have other source origins.