In order to meet the increasingly severe snubbing operation environment，a kind of plugging material with wide applicability and excellent performance was prepared by using polyacrylamide（HPAM），cross-linking agent Smel 30，corn starch and ammonium chloride as raw materials in the laboratory. The effects of coagulant，temperature，pH value，metal ions and simulated oil on the gelling properties of the system were studied by rheological method. In addition，the stability and breakability of the gel was evaluated. The experimental results showed that the optimal pH range of the gel system，composed of 3% corn starch， 0.5% cross-linking agent Smel 30，0.8% ammonium chloride and 1% HPAM，was 5—9，which is especially suitable for weakly alkaline reservoirs；metal ions had little effect on gelation time and gel strength. The gelation time of the gel could be controlled at the range of 6—20 h by adjusting the amount of coagulant，and the gel strength of the obtained gel could reach J level. Under the laboratory conditions，the gel could be effectively broken with ammonium persulfate within 2 h. The viscosity of the gel-breakingfluid reduced to 300 mPa·s，indicating the gel was easy for flowback.