Objective：To evaluate the ventricular systolic function of fetuses with gestational diabetes mellitus（GDM）by using 24-segment two-dimensional speckle tracking imaging（2D-STI）technique. Methods：A total of 111 singleton pregnant women in Changzhou second people’s Hospital affiliated to Nanjing Medical University from May 2020 to August 2021 were collected and divided into GDM group and normal control group according to the results of oral glucose tolerance test（OGTT）. All pregnant women underwent fetal echocardiography to obtain routine fetal echocardiographic evaluation indexes，including left ventricular ejection fraction（LVEF），left ventricular cardiac output（LVCO），area change fraction（FAC），cardiac globular sphericity index（GSI），mitral annulus plane systolic displacement（MAPSE），tricuspid annulus plane systolic displacement（TAPSE）. At the same time，24-segment 2D-STI technique was used to obtain fetal ventricular strain indexes：left ventricular global longitudinal strain（LVGLS），left ventricular global circumferential strain（LVGCS），right ventricular global longitudinal strain（RVGLS），right ventricular free wall strain（RVFWSt）. Results：There was no significant difference in traditional echocardiographic evaluation indexes and LVGLS between the GDM group and the normal control group，but the fetal LVGCS，RVGLS and RVFWSt in the GDM group were significantly lower than those in the normal control group（P＜0.05）. There were positive correlations between LVGLS and LVEF，LVFAC（r=0.544，0.714，P＜0.05），between LVGCS and LVEF，LVFAC，MAPSE（r=0.837，0.751，0.191，P＜0.05），and between RVGLS，RVFWSt and RVFAC（r=0.517，0.421，P＜0.05）. Maternal body mass index（BMI）was an independent predictor of RVGLS（β=0.496，95%CI：0.147~0.846，P＜0.05）. Conclusion：GDM can cause the decrease of fetal ventricular systolic function. 24-segment 2D-STI technique can monitor fetal ventricular systolic function timely and accurately，which is beneficial to clinical pregnancy monitoring.