In view of strong reservoir heterogeneity，thick oil layers and large well spacing in the offshore oilfield，a polymer gel with controllable gel strength for deep profile control and oil displacement was developed. Gel strength modifier tert-butyl hydroperoxide（TBHP）was added into common organic phenolic resin gel to adjust the gel strength. The effects of the tert-butyl hydroperoxide（TBHP）on gelation time and gel strength were studied. The microstructures of the novel gel at different aging times were observed by scanning electron microscopy（SEM）to analyze the gel strength change mechanism.The transport properties of the novel gel in porous media were evaluated by monitoring the pressure distribution during water flooding after gelation in porous media at different aging times. Results show that the effect of gel strength modifier on gelation time is not obvious. As the aging time and gel strength modifier concentration increase，the gel strength decreases gradually under reservoir temperature and the gel strength modifier. Compared with the conventional gel，the network structure of the novel gel is destroyed more seriously and it can migrate in porous media after aging for 30 d.