The influence of emulsified oil, suspended solids, Fe~(3+), Fe~(2+), cationic water clarifier and sulfate-reducing(SR) bacteria on the aggregation behavior of residual hydrophobic modified polyacrylamide in treated oily wastewater from polymer flooding was studied by fluorescence spectroscopy and dynamic light scattering.The result of I_1/I_3 showed that the polarity of hydrophobic microdomains increased, whereas the size of the hydrophobic microdomains may be decreased, where the value of I_1/I_3 represents the ratio of the intensity of peak I_1(374.0 nm) to that of peak I_3(385.0 nm) of the vibration fine structure of pyrene monomer emission in residual polymer solution. The results of the ratio of I_1 at 48 h to I_1 at 0 h(I_(1,48h)/I_(1,0h)) indicated that oil and cationic water clarifier could inhibit the aggregation to some extent, while Fe~(2+)and suspended solids were helpful for aggregation,and Fe~(3+)and SR bacteria had no significant influence on the aggregation of polymer. The influence of emulsified oil, suspended solids, Fe ~ (3+), Fe ~ (2+), cationic water clarifier and sulfate-reducing (SR) bacteria on the aggregation behavior of residual hydrophobic modified polyacrylamide in treated oily wastewater from polymer flooding was studied by fluorescence spectroscopy and dynamic light scattering. The result of I_1 / I_3 showed that the polarity of hydrophobic microdomains increased, whereas the size of the hydrophobic microdomains may be decreased, where the value of I_1 / I_3 represents the ratio of the intensity of peak I_1 (374.0 nm) to that of peak I_3 (385.0 nm) of the vibration fine structure of pyrene monomer emission in residual polymer solution. The results of the ratio of I_1 at 48 h to I_1 at 0 h (I_ (1,48h ) / I_ (1,0h)) indicated that the oil and cationic water clarification could inhibit the aggregation to some extent, while Fe ~ (2+) and suspended solids were helpful for aggregation, and Fe ~ (3+) and SR bacteria had no significant influence on the aggregation of polymer.