Objective To explore the clinical relevance of the pregnant women serum PAPP -a, IR and gestational diabetes. Methods The 160 cases of gestational diabetes mellitus were treated in our hospital from April 2013 to April 2014 as the observation group, and the normal pregnant women were treated as the control group. The differences of serum PAPP-A levels and IR values in the two groups were compared and analyzed. Results The serum PAPP-A level of the observation group was significantly lower than that of the control group, while the IR value was significantly higher than that of the control group, the difference was statistically significant (P<0.05). Conclusion The level of serum PAPP-A and IR in pregnant women is significantly related to the gestational diabetes mellitus. The serum PAPP-A of the patients with gestational diabetes is significantly decreased, while the IR is significantly increased, which can provide reference for clinical diagnosis.