Abstract: According to the short of injection volume and high injection pressure in polymer injection block of Shuanghe Oilfield, the characteristics of the polymer injection such as injection speed, the pressure gradient, polymer concentration, the core permeability, as well as the effect of polymer viscosity on injection properties were studied. The experimental results showed that the polymer injection concentration was the most influential factor, and the injection rate was the least one. Rock permeability affected the injection of polymer solutions and propagation in the formation. When core permeability was less than 0.8 μm², the rear plugging was greater than the front because of the combined action of mechanical trapping and adsorption. With the core permeability increased (> 0.8 μm²), polymer solution could be injected further and the plugging mechanism was only adsorption of polymers, which caused minor blockage. At the same time, the pressure gradient at the rear of the core in the polymer flooding was the highest, which indicated that the blocking part mainly occurred in the posterior part of the core. After adjusting the polymer concentration in the field, it was found that the maximum drop rate of the short of injection volume is 35%, which showed that the injection properties of polymer injection wells could be improved effectively. It is a favorable way to increase the pressure and increase the injection.