With the end of the block of polymer flooding area or the late effect，the dominant percolation channel is more prominent， and the difficulty of effective mining is increased. In view of the demand for fixed plugging in the deep fixed point after polymer flooding，in order to further tap the remaining oil and reduce the ineffective circulation of the injecting fluid in the process of production and development after polymer flooding，a low initial viscosity controllable gel plugging agent，composed of hydrolyzed anionic polymer with molecular weight of 25 million，metalion crosslinker，regulator，retarder，strengthening agent，was developed，and the performance of gel plugging agent system was evaluated. The results showed that the formulation of the system prepared with reclaimed wastewater was as follows，500—1000 mg/L polymer LH2500+1000—2500 mg/L cross-linking agent CYJL+200—500 mg/L regulator（citric acid）+ 100—150 mg/L retarder（sodiumsulfite）+ 100—200 mg/L enhancing agent（polyphosphate sodium），the initial viscosity of the system was low，being of within 10 mPa·s，and the gelation time was controllable within 10—30 days，and the gelling viscosity was above 2000 mPa·s. the tolerance to salinity was up to 20000 mg/L，and the suitable pH range was 8—9. The system has better core plugging performance，the blocking rate of the system to the core with the permeability of 0.48—3.9 μm² was more than 99%，and the residual resistance factors was in range of 95.6—396.1.The results of the three-layer parallel core experiments indicated that the system had less pollution to the mid-low permeability core，meeting the in-sit plugging demand.