Objective The purpose of this study was to evaluate the clinical value of Doppler ultrasound in the evaluation of the curative effect of pylorotomy under gastroscopy in the treatment of congenital hypertrophic pyloric stenosis （CHPS）. Methods The pylorus of 65 children with CHPS and 50 control infants were examined by Doppler ultrasonography. The thickness and blood flow grading of pyloric muscular layer and mucosal layer were compared. To observe and compare the changes of blood flow distribution and parameters of pyloric duct in children with CHPS before operation and 1 day, 1 week, 1 month and 6 months after gastroscopic pylorectomy.At the same time，the changes of the pylorus tube and the diameter of the pylorus tube were observed. Results The thickness of muscular layer and mucosal layer, blood flow grading of muscular layer and mucosal layer in CHPS group and control group were statistically significant(P＜0.01). In group CHPS, blood flow in mucosa was more abundant at 1 d after operation；after 1 weeks and 1 months of pyloric diameter，muscular layer thickness，6 months after surgery，muscle thickness further thinning，muscular layer and mucosa and submucosa blood flow compared with preoperative sparse reduced，Vmax and RI of muscle layer decreased. Conclusion By Doppler ultrasound，we can grasp the blood flow grading of pyloric canal mucosa after gastroscopic pylorotomy，and estimate the degree of pyloric stenosis by measuring Vmax and RI. It provides valuable clinical evidence for evaluating the effect of surgical treatment.