Abstract: Objective To investigate the clinical significance of cardiac axis determined by echocardiography in the diagnosis of fetal congenital heart disease (CHD).Methods 528 high risk fetuses for CHD were examined by echocardiography.Cardiac axis was measured on four chamber view and fetal cardic anatomical structure was examined in multiple views to determine CHD.Re-sults 29 cases of fetal congenital heart disease and 499 cases of normal fetus were detected by four chamber view in 528 cases of congenital heart disease risk in the fetus pure.However,43 cases of fetal congenital heart disease and 485 cases of normal fetus were detected by combination of four Chamber view and cardiac axis determination in 528 cases of congenital heart disease risk in the fetus pure(P <0.01).Finally,46 cases of fetal congenital heart diseas were diagnosed through perinatal autopsy,newborn ultrasound examination or the results after diagnosis.Sensitivity of CHD diag-nosed by four chamber view alone was 63.04%.However,it was elevated to 93.48% by combina-tion of four Chamber view and cardiac axis determination (P <0.05).Conclusion Cardiac axis plays a key role in fetal echocardiographic screening for CHD.