The long-term water flooding in oilfields leads to high water cut in oil wells, requiring environmentally friendly, low-cost, high-quality, and efficient chemical plugging agents for oilfield profile control. In this study, a thermoplastic flexible particle plugging agent was prepared by adding rubber powder. Experimental results showed that the rubber powder blended flexible particles had an appropriate particle size distribution and a porous structure. Compared to the particles without rubber powder, the rubber powder blended flexible particles exhibited higher thermal stability and better mechanical properties, including hardness, elasticity, cohesiveness, and recoverability. The flexible particles remained stable in high-temperature and high-salinity water, and exhibited good thermoplasticity by undergoing cohesion at high temperatures. Physical model experiments demonstrated that the rubber powder blended flexible particles could generate stable pressure difference fluctuations, quickly adapt to fractures’ deformation and pressure changes, and form effective plugging. In summary, the rubber powder blended flexible particles possess excellent deformability, thermal stability, and injection performance, making them suitable for addressing the problem of deep fluid diversion in oilfields and enhancing oil recovery.