Integrated Intelligent Water Injection Device is designed specifically for small-scale and flexible water injection stations in oilfields. It involves incoming water being pressurized by feedwater pumps and injected into water injection wells by injection pumps. This device is suitable for on-site water injection and early-stage water injection projects. It offers high water injection efficiency, low production costs, and minimal safety risks. It can replace small-scale water injection stations and is applied in advance water injection in oilfields, development of remote small blocks, boosting in high-pressure under-injected wells, and water reinjection of produced water.