Bacterial activities of dam reservoir sediments were assessed using the methods of viable counts, ATP contents, dehydrogenase activity, and oxygen consumption. Viable heterotrophs in collected sediments were observed in the range of $10^6{sim}10^{10}$ CFU/g dry wt. sediment. All assessed methods showed high activities in sediment samples collected from near dam site. In addition, bacteria increase in sediments amended with cellulose, starch, lipid, and protein compounds. Various ranges of antibiotics and heavy metals resistance bacteria were also detected, especially, 10~100 times less numbers of Cd resistance bacteria were observed compared with those of Pb and Cr. In general, antibiotics resistance groups were in the range of $10^{-1}{sim}10^{-6}$ times of control.