In order to improve the curing strength of the sealing and channeling agent system in ASP flooding environment and improve the plugging effect of external channeling well after ASP flooding，through investigating the influence of the concentrations of main agent（a mixture of irradiated acrylamide and bentonite grafted semi-copolymerized polymer derivatives）， crosslinking agent（ammonium persulfate），reinforcing agent（N，N-methyl-diacrylamide），micro-expansion agent（OP-10 and sodium dodecyl benzene sulfonate）and hardening agent（G grade cement）on curing effect，a slightly expanded sealing and channeling（SESC）system suitable for ASP flooding was obtained. The long-term stability of solidified body of SESC system in ASP flooding system and the compatibility between the SESC system and ASP flooding system were studied，and the plugging performance test of the SESC system on the core in ASP flooding system and the field plugging and channeling test were carried out. The optimal recipe of the SESC system was as follows：13%—17% main agent+0.12%—0.18% crosslinking agent +0.06%— 0.09% reinforcing agent +0.3%—0.5% OP-10 or 0.8%—1.0% sodium dodecyl benzene sulfonate+5%—7% hardening agent. The curing time of the SESC system was 1—5 h. The minimum strength of the system could still exceed 20 N，and the volume expansion multiple was less than 1.5 times after 12 months immersion in ASP environment. After soaking，the volume inflation of the system was controllable and the high strength stability was maintained. The core sealing experiment showed that the breakthrough pressure reached above 10.0 MPa and the core plugging rate exceeded up to 97%，which proved that the SESC system possessed excellent plugging ability. The field sealing test showed that the total well fluid production decreased by 30.3%，the maximum oil production increased by 1.58 t，and the water cut decreased by 4.1% after the SESC system was used to seal the cross-flow horizon of a well. The SESC system had good sealing effect on cross-flow wells after ASP flooding.