Objective To explore the clinical signification of polyethylene glycol screening method on the diagnosis of hyperprolactinemiat.Methods We selected 260 patients with hyperprolactinemia as observation group and 80 healthy individuals as control group. The two groups were measured with Abbott laboratories I2000 automatic chemiluminescence detector about the concentration of PRL. Then the groups were measured again after they were precipitated by the polyethylene glycol and the result data were analyzed.Results 78 cases of MP were checked out from the observation group and 3 cases were checked out from the control group. The proportion was 25.77% and 3.75% respectively, and the differences were statistically significant (P＜0.05). The difference of the concentration of PRL before precipitated by PEG among the HP group, the MP group and the control group were statistically significant (P＜0.05). After precipitating, the difference of the concentration of PRL between the HP group and the MP group were statistically significant (P＜0.05), as well as the HP group and the control group. However, there was no difference between the MP group and the control group (P＞0.05). The checking conditions of MP in some diseases caused by HP had no difference(P＞0.05).Conclusion The use of polyethylene glycol screening method is a practicable method to eliminate the interference of MPRL on the diagnosis in HP. It has significance reducing misdiagnosis rate of HP.