Abstract: In view of invalid of water injection in high water cut oilfield,and formed high permeability zone,block of it by chemical block agent is effective.The performance of block agent effect the effectiveness of blocking,so laboratory and field experiment of polymer gel block agent were done to enhance its blocking effectiveness.Sealing characteristics,resist erode performance,flow gelled performance,and flow orientation change capacity were tested in laboratory by core and tri-tube experiments.Also,field blocking testing was done by polymer gel block agent made up by polymer gel and sewage of oilfield.The experiment shows that polymer gel has preferably seal and resist erode capability,and has perfect intensity,two wells application have obtained evidently effectiveness,which provide successful experiences for polymer gel applications in high permeability zone.