Abstract: As a conventional water control technology, profile control is widely used in water flooding and polymer flooding oilfields, but due to space limitation on the drilling platform in offshore oilfield, the conventional profile control equipment cannot be laid out on the platform and cannot be used normally. Hence, research was carried out on using polymer flooding process to realize profile control by on-board mixing and surface mixing and injection technology, which addressed the problem of conventional profile control equipment occupying large area and was pilot tested in individual well in JZ9-3 Oilfield in Bohai. The results show that the profile control technology of polymer flooding on-board mixing offshore is a simple technique, occupying small area, safe and reliable, addressing the problem of polymer channeling, and achieving significant increase in oil production and reduction in water production, providing a reference method for plugging similar polymer channeling.