Objective To evaluate the effect of Gestational diabetes mellitus (GDM) on neonatal cardiac function and structure by two dimensional ultrasound speckle-tracking imaging (STI).Methods Two-dimensional active images of left ventricular at basal short-axis view and the thickness of left ventricular wall were acquired in 45 infants of gestational diabetes mellitus mothers and 45 normal neonates and left ventricular torsion was calculated by STI.Results The interventricular septal thickness of GDM group was (0.45 ± 0.06) cm,while that of the control group was (0.34 ± 0.05) cm,with significant difference (P<0.05).The posterior left ventricular wall thickness of GDM group was (0.45 ± 0.17) cm,while that of the control group was (0.31 ± 0.02) cm,with significant difference (P<0.05).The peak endomembranal rotation of GDM group was (-4.713 ± 2.049)°,while that of the control group was (-3.744 ± 1.854)° ;the peak bulk rotation of GDM group was (-2.351 ±1.429)°,while that of the control group was (-1.413 ± 0.918)° ;the peak membranal rotation of GDM group was (-1.457 ± 1.135)°,the control group was (-0.916-± 0.808)° ;The peak mural torsion of GDM group was (-3.209 ± 1.326)°,the control group was (-2.886 ± 1.481)°.The left ventricular torsion in GDM group was higher than that of control group with significant difference (P<0.05).Conclusion The Cardiac function and structure of infant of gestational diabetes mellitus mother are impaired.STI can exactly evaluate the characteristics of neonatal cardiac function. Key words: Two dimensional ultrasound speckle-tracking imaging; Gestational diabetes mellitus (GDM); Cardiac function; Left ventricular torsion