In order to improve the effectiveness of water plugging in offshore fluvial heavy oil reservoirs, the selective water plugging study of offshore fluvial heavy oil reservoirs was carried out in combination with the typical reservoir and fluid characteristics of Bozhong Oilfield.Laboratory experiments were conducted to compare the performances of three kinds of plugging agents selected and prepared from four aspects: injection capacity, water plugging validity period, plugging capacity and damage degree to low permeability formation.The results show that plugging agent A has the best injection performance and the lowest permeability damage,plugging agent B has the best plugging performance, and plugging agent C has the longest water plugging validity.Combining reservoir characteristics of target oilfield and operation requirements of offshore platform,plugging agent A is selected as the best water plugging system and has been applied in Bozhong Oilfield. After water shutoff, the maximum daily oil increase of is about 35m3, the water cut is reduced by about 10%, the validity period is 13 months,and the cumulative oil increase is 1.4 × 104m3, which has achieved a good effect.