For determing the ecological roles of free-living bacteria and epiphytic bacteria on marophytes (Acorus calamus, Nymphaea tetragona, Nymphoides indica), the β-glucosidase activities of free-living and attached bacteria were investigated at two ponds weekly from May, 1995 to August, 1995. The β-glucosidase activities of pond water of Yeonjeokji and Sesimjeong were ranged 35∼1073 nmol 1^-1 hr^-1 and 30∼898 nmol 1^-1 hr^-1, respectively. At Yeonjeokji, where the phytoplankton was abundance, the variations of β-glucosidase activity correlated with the chlorophyll a concentration, while at the Sesimjeong, where the macrophyte was abundance, the correlation between activity and chlorophyll a concentration was not appeared. The areal activity of A. calamus, N. tetragona, N. indica were varied 16∼437, 223∼149537 and 19∼2396 nM cm^-2 hr^-1, respectively. The lowest areal peaks of activities of three macrophytes were appeared during the flowering period. At Yeonjeokji, the specific activity of epiphytic bacteria on N. tetragona was higher than that of free-living bacteria during the late spring, but it was lower during the summer. In other hand, the specific activity of epiphytic bacteria on N. indica, was 200∼500 times higher than that of free-living bacteria. At Sesimjeong, variation of the specific activity of epiphytic bacteria on A. calamus was similar to that of free-living bacteria. These results suggest that bacterial mineralization rates are affected by the kind of macrophytes, their physicological state and limnological characteritics.