Objective To observe the correlations of two-dimensional speckle tracking imaging(2D-STI)parameters of healthy fetal heart and gestational age in middle and late pregnancy.Methods Fetal echocardiography was prospectively performed in 279 healthy singleton fetuses in middle and late pregnancy.The fetuses were divided into group A(20-23+6 weeks of pregnancy,n=49),B(24-27+6 weeks of pregnancy,n=112),C(28-31+6 weeks of pregnancy,n=63),D(32-35+6 weeks of pregnancy,n=30)and group E(≥36 weeks of pregnancy,n=25)according to gestational age.Fetal left ventricle(LV)ejection fraction,LV and right ventricle(RV)area change fraction,LV and RV global radial strain(GRS),LV and RV myocardium and endocardium global longitudinal strain(MyoGLS,EndoGLS),LV myocardium and endocardium global circumferential strain(MyoGCS,EndoGCS)were obtained with 2D-STI and compared among 5 groups,and the correlations with gestational age were analyzed.Results Significant differences of fetal LV EndoGLS was found among 5 groups(P=0.044).Fetal LV GRS and RV GRS were positively correlated with gestational age(r=0.165,0.122,both P＜0.05)in middle and late pregnancy,while the absolute value of LV EndoGLS was negatively correlated with gestational age(r=-0.133,P=0.026).Conclusion LV GRS and RV GRS were positively correlated with gestational age in healthy fetuses in middle and late pregnancy,while the absolute value of LV EndoGLS was negatively correlated with gestational age.