A newly modified functional polymer with a molecular weight of approximately 7 to 9 million was synthesized on the basis of polyacrylamide (PAM) for use in type 3 oil layers[1].The viscosities of the new polymer and of HPAM with similar molecular weights were measured in de-ionized water and brine.The mobility and recovery factor of the new polymer also was calculated.The results indicated that the new polymer had higher viscosity and salt resistance in brine;furthermore, it yielded higher coefficients of resistance and residual resistance, indicating better injection and mobility.The polymer was able to enhance the recovery factor of type 3 oil layers by more than 7%, which was far higher than the 4% recovery factor increase achieved by the reference polymer.It was concluded that the new polymer exhibited better adaptability in type 3 oil layers and could be further applied industry.