When the cattail pollen was identified by using fibrinolytic agents, we found that the fibrinolytic activity was controlled by an enzyme. Therefore, for determining the fibrinolytic activity of cattail pollen, the fibrinolytic enzyme in cattail pollen was purified by gel filtration using DEAE-cellulose, Sephadex G-150 and HPLC. Also, its purity was certified by polyacrylamide gel electrophoresis, and its physico-chemical properties, such as pH and temperature stabilities and effects of metal, inhibitors and substrates, were examined. The specific activity, purification fold, and molecular weight of the enzyme were 38U/mg, 86.4,and 75kDa, respectively. The optimum pH for the purified enzyme was at 4.0 and it was stable at pH 4.0-6.0. The optimum temperature was $55^{circ}C$ and it was stable at $30-60^{circ}C$. But the enzyme began to be inactivated at $70^{circ}C$ and its activity was totally lost at temperatures above $80^{circ}C$. As for substrate specificity, the enzyme was most effective in dissolving fibrin, followed by whole casein, ${kappa}$-casein, ${alpha}$-casein, ${eta}$-casein, and BSA. With casein as the substrate, Km value was found to be 0.44mM and the enzyme showed a high affinity for casein. As for the metal ions affecting enzyme activity, $K^+$, $Na^+$, and $Mg^{2+}$ had no effect on enzyme reaction while $Zn^{2+}$ and $Fe^{2+}$ showed potent inhibitory activity. Judging from the fact that the purified enzyme was also strongly inhibited by PMSF, iodoacetic acid, and SDA, it assumed to be a serine protease.