Aiming at the problem of high injection pressure caused by particle migration blocking the reservoir pore throat in the process of water injection in high clay loose and low permeability sandstone reservoir, a neutral gradient anti plugging system was optimized through laboratory experiments. The low-speed gradient anti plugging system is 0.5% KCl clay stabilizer, and the high-speed gradient anti plugging system is 0.2% KCl + 0.3% organic cationic clay stabilizer. The anti-swelling property of gradient anti plugging system and the changes of core pressure and permeability during displacement were investigated. The results showed that the anti-swelling rate of the system was more than 91%. Compared with the blank production water displacement, at low speed, after being treated by the anti-plugging system, the pressure growth multiple was reduced from 5.41 to 2.03, and the permeability retention rate was increased from 18.49% to 49.15%; At high speed, after being treated by the anti-plugging system, the core permeability gradually recovered. When 8PV was replaced by production water, the permeability retention rate increased from 10.56% to 91.58%, and the pressure growth multiple decreased from 9.47 to 3.28. The plugging prevention system is neutral, which provides a strong support for the advanced green water injection and efficient development of low permeability reservoirs.