In the mature oilfields, most of injected water passes through fractures and high permeability zones in reservoir and barely goes into the low permeability zones containing significant volumes of hydrocarbons, resulting in high water production and poor oil recovery. A common way to control conformance (correct reservoir heterogeneity) is injecting preformed particle gel (PPG) into reservoir to plug the highly permeable zones and fractures. Nevertheless, traditional PPG just swells but does not dissolve to thicken formation water to displace crude oil. In this work, labile cross-linker, water-soluble polyacrylamide and laponite were hybridized to get structurally-“tailored” novel degradable PPG. Under high-temperature reservoir environment, the labile cross-linker partially de-crosslink to free some of the water-soluble chains thus to viscosifying the displacing fluid while keeping such PPG particles to be swelled. In 1.5 wt% NaCl solution at 80°C, such hybrids can gradually swell above 7 times within months before complete decomposition. At the same time, the apparent viscosity of 0.2 wt% particle suspension slowly increases 20-fold because of the electrostatic interaction between soluble degradation product and laponite released from the particle. Such double functions furnish these particles great potential to be used in oilwell water shutoff.