Abstract: To study the complex flow characteristics of polymer solutionin reservoir porosity, experiments were carried out for the flow of partially hydrolyzed polyacrylamide (HPAM) solution in tubes of 10\sim350\mum in diameter. The results show that under theexperimental conditions specified in this paper, the flow laws of HAPMsolution significantly deviate from those ofnon-Newtonian fluid mechanics in conventional scales. When the diameter of tubes is small, itsaverage cross-section flow velocity is higher than the conventionalresult. The smaller the tube diameter, thegreater the deviation will be.