The hacterioplankton production and bacterioplankton abundance were surveyed in dilution zone of the Changjiang Estuary and a mesocosm experimental device for enriched phosphate experiment and oil contaminated experiment was placed in the waters nearby Luhua Island during October 1997 and May 1998. The results showed that the average bacterioplankton production in spring was higher than that in autumn, the production at the surface water was higher than that at the bottom in the surveyed area; the higher values appeared in the middle of the area. The results from mesocosm experiment with adding phosphate and oil contaminated showed that the bacterioplankton production increased rising trend day by day during the experiment period.