In order to improve the poor stability and breakage of pre-crosslinking gel particles and the effect of gradual deterioration after multi-round profile control，a granular fracture plugging agent with high strength and soft elasticity was prepared by using aromatic monomer and special comonomer as main agent and benzoyl peroxide as initiator. The mechanical property of the plugging agent was studied and it was applied in Changqing fractured reservoir. The results showed that the hardness of plugging agent was small and the flexibility was good，which was good for pump injection. The change of shore hardness of plugging agent at low temperature was small. The value of shore hardness was 18.6—18.9 HA at 18—28℃ . The strain increment of plugging agent increased and the storage modulus decreased with the increase of temperature. Temperature had little effect on the loss modulus of plugging agent. The elongation at break of plugging agent was 1352%—1358%，and the corresponding tensile stress was 1.20— 1.56 MPa. The compressive deformation ability of plugging agent was good. When the compressive stress increased，the strain increased gradually. The salinity of formation water had little effect on the flexibility of plugging agent. The plugging agent had good effect in the field application of Ansai oilfield with the input-output ratio of 1∶2.92 and cumulative oil increment of 3768 t. It had effectively improved the problem of using pre-crosslinking gel particle profile control agent.