Gel water shutoff agent

The invention discloses a gel water shutoff agent for suppressing and stabilizing fine silt and capable of effectively reducing high permeability during oil production. The gel water shutoff agent consists of the following components in percentage by mass: 30-40% of poly dimethyl diallyl ammonium chloride, 5-15% of ammonium chloride, 10-20% of ethylenediamine dihydrochloride and 20-40% of water. When in use, the gel water shutoff agent is substantially a gel particle which can form a bridge and accumulate in reservoir pores and also can form a 'sand plug' under the bonding effect of tiny mineral particles in the reservoir so as to realize an aim of adjusting the infiltration capacity of water flow at a high-infiltration part. Two major problems of high water content and fine silt generation in the superficial unconsolidated sandstone reservoir are solved well; and moreover, the dosage is small, the cost is low, and the application prospects are wide.