Objective To explore the roles of dynamic electrocardiography (DCG) combined with echocardiography in the evaluation of cardiac function in patients with preexcitation syndrome. Methods A total of 87 patients with preexcitation syndrome who received Holter monitoring and echocardiography from January 2012 to June 2019 in our hospital were enrolled in this study and served as the study group. And another 87 individuals without identified heart disease who received the two examinations at the same period were subjected to normal control group. The differences in the indices of Holter and echocardiography were compared between the two groups. SPSS statistics 21.0 was used for statistical analysis. Intergroup data comparison was performed using t text or Mann-whitney U test. Results The pulmonary artery diameter [(20.77±2.61) vs (19.94±2.19) mm], left atrial transverse diameter [(32.44±4.86) vs (30.93±3.21) mm], interventricular septal thickness [(10.1±2.37) vs (9.26±1.33) mm], left ventricular diastolic diameter [(44.55±4.33) vs (42.91±4.07) mm] and aortic velocity [(130.91±34.60) vs(118.95±21.42) cm/s] were all significantly larger (P<0.05), but left ventricular ejection fraction was obviously lower [(64.93±5.93)% vs (66.95±5.04)%, P<0.05] in the study group than the control group. There was no significant difference in the indicators of heart rate variability between the two groups. Conclusion Echocardiography can be used as a reference for the diagnosis of preexcitation syndrome related cardiac morphological changes. Further study should be performed for the diagnostic significance of the indicators of heart rate variability by DCG for preexcitation syndrome.