Aimed at the problem that the formation fluid can not be plugged effectively to prevent the fluid from flowing upward during the process of the precise pressure control drilling due to the lower compressive and cementation strength，much aperture and fracture of the solid packing formed by hydraulici gel，a kind of waterborne epoxy resin CQ-WERE and matched curing agent CU-900 as the properties modification agent（PMA）was added into the hydraulic gel working fluid（HGWF）and the influence of the PMA on the rheology of HGWF and mechanical property of solid packing formed by HGWF was investigated，and the mechanism that the PMA improved the mechanical property of the solid packing was analyzed. The results showed that the PMA had good compatibility with the HGWF，the PMA had less influence on fluidity and rehology property of the HGWF；the thickening time of the HGWF decreased with the PMA dosage increased；the PMA could significantly improve the compressive strength of the solid packing and cementation strength between the solid packing and the pipe surface，with PMA dosage of 3%，after curing at the temperature of 120℃for 5 h，the compressive strength and cementation strength could increased up to 4.61 MPa and 1.39 MPa/m，respectively；meanwhile，the self-cementing ability of the gel packing was good，the air sealing pressure being not less than 1.02 MPa/m；the drillability grade of the solid packing was 2，meaning that the solid packing could be easily drilled out. When the PMA was added to the HGWF，the water-reducing and solidification crosslinking effect was achieved，which could modify the organization structure of the solid packing，decrease the micro-defect，strengthen the compactness，prevent fracture from propagating and improve the mechanical property of solid packing.