Objective Four echocardiographic methods for assessing Kawasaki disease (KD) complicated with coronary artery abnormalities were analyzed to provide a basis for early accurate clinical assessment. Methods The KD children combined with coronary artery lesions who were hospitalized in the Department of Cardiology from December 2017 to July 2020 were selected as the study subjects. Three Z-value formulas (Kobayashi, Dallaire and Olivieri) and 1988 domestic standard were used to evaluate the coronary artery abnormalities caused by KD. Results A total of 94 patients (59 boys and 35 girls) were enrolled with a median age of 18.1 (7.3-31.7) months. There were statistically significant differences in the lesions degree evaluation of proximal right coronary artery (pRCA), left main coronary artery (LMCA) and left anterior descending artery (LAD) among the four coronary artery lesions assessment methods (P<0.01). The detection rate of large coronary aneurysms in pRCA by Olivieri method was significantly lower than that by Dallaire method (P<0.05). The detection rate of Olivier method was significantly higher than the other three methods in the evaluation of normal and only dilated LMCA (P<0.05). For small coronary aneurysms, the detection rate of Olivier method was significantly lower than Kobayashi method and domestic standard in 1988 (P<0.05). Dallaire's detection rate was significantly higher than Kobayashi's and Olivieri's for large coronary aneurysms of LAD (P<0.05). When evaluating the right coronary artery (RCA) using the Dallaire method, it was found that if the pRCA was measured alone, the extent of RCA lesion expansion in 11.7% of patients would be underestimate, as well as 52.1% of middle RCA lesions and 27.7% of distant RCA lesions would be missed. Among the children who measured the middle of LAD, 30% of the children with abnormal middle of LAD were missed by Z-value evaluation of the proximal LAD alone. Conclusions In order to reduce the misdiagnosis of coronary artery lesions at the early stage of KD, all the different segments of the 4 coronary arteries should be measured as much as possible by echocardiography. The proximal and distal segments of RCA should be evaluated by Dallaire method. The criterion of a dimension >1.5 times should be used for the middle of LAD. For the middle of LAD, a ratio greater than 1.5 times the diameter of the surrounding segments is recommended.