In response to the problem that a large number of metal ions in seawater adhere to the surface of guanidine gum, which inhibits the swelling of guanidine gum molecular chains and cannot meet the continuous mixing in the field, epichlorohydrin and octadecenoic acid amidopropyl dimethyl as raw materials were synthesized and cationic monomer GOA was obtained, and then GOA was grafted onto guanidine gum molecular chains to obtain seawater-based fracturing fluid thickener epoxy propyl surfactant modified guanidine gum. Coulombic forces and electrostatic repulsion on the molecular chains of the modified guanidine gum prevented metal ions from attaching to the molecular chains of the guanidine gum, ensuring the swelling of the guanidine gum molecules and improving the salt resistance of the guanidine gum. The dissolution, salt resistance, temperature and shear resistance, sand-carrying and glue-breaking properties of GOA modified guanidine adhesive were investigated in the paper. The results show that the dissolution rate of GOA-modified guanidine gum in seawater is significantly higher than that of ordinary guanidine gum, and the median particle size in seawater is about 1/5 of that of ordinary guanidine gum molecules; the viscosity of GOA modified guanidine gum can reach 80% of the final viscosity after 5 min of swelling at 500 r/min; microscopic analysis shows that GOA-modified guanidine gum forms a clearly visible irregular mesh nematic structure, and the guanidine gum molecular chain The microscopic analysis showed that the GOA modified guanidine gum formed a clearly visible irregular net-like nematic structure, and the molecular chains of guanidine gum were fully expanded and the cross-linked bonds increased. The viscosity was still higher than 50mPa·s after continuous shearing at 160℃ and 170s-1 for 120min, indicating that the GOA modified guanidine glue fracturing fluid has good salt, temperature and shear resistance and the viscosity of the broken fluid is 1.6mPa·s. The residue content in the broken fluid is 297mg/L, which meets the requirements of field fracturing construction.