Abstract: In PGNAA measurement, the distributions of neutron field and γ-ray self-absorption in samples have an influence on the measurement results. A corresponding correction model with two effects into consideration and a theoretical calculation were carried out with an aqueous solution element detection setup. The theoretical calculation was applied to measurement results of detecting device by Monte Carlo simulation. After modification on the theoretical model, the results show that influence of neutron field and γ-ray self-absorption on PGNAA measurement decreases.