1. Objective To explore the value of Gastric three-dimensional volume ultrasonography and iodinated water contrast agent fluoroscopy in G-POEM, so as to choose more suitable imaging examination method clinically. 2. Methods A total of 93 patients with gastroparesis were divided into two groups according to the different methods of gastric emptying who were diagnosed by gastroenterologists in Southeast University affiliated Zhong Da hospital: group A constituted of 48 cases (three-dimensional gastric volume examination) and group B constituted of 46 cases (X-ray iodinated water contrast examination). Group A was examined at 5, 15, 30, 60 and 90 minutes after oral administration of contrast agent. In 3D ultrasound measurement, group B took the upper abdominal X-ray plain film at the same time point after taking the iodinated water contrast agent. The above methods were measured before and after g-poem operation, and the gastric volume before and after g-poem operation was estimated by three-dimensional ultrasound contrast method and iodine water contrast method respectively, from which the efficacy rate of G-POEM operation was evaluated and compared. 3. Results 1). The success rate of three-dimensional contrast-enhanced ultrasonography was 97.9% in group A, 97.8% in group B, and there was no significant difference between the two groups (P > 0.05); 2). The gastric emptying time decreased significantly in 31 cases of group A and in group B, significant reduction of gastric emptying time was seen in 31 cases. In both groups, the gastric emptying time decreased from 90 (90, 90) minutes before operation to 30 (15, 60) minutes after operation (P < 0.05). 3). In group A, among 16 patients whose gastric emptying time was 90 minutes before and after operation, 8 cases had significant improvement in the gastric emptying volume rate after operation, which increased from 61.6% (55.9%, 73.6%) before operation to 78.1% (74.1%, 91.6%) after operation (P < 0.05), and in 8 cases no significant improvement was observed (P > 0.05). Similarly, in group B, among 14 patients whose gastric emptying time was 90 minutes before and after operation, 5 cases had significant improvement in the gastric emptying volume rate after operation, was increased from 25.0% (25.0%, 50.0%) before operation to 75.0% (70.0%, 90.0%) after operation (P < 0.05), and in 9 cases no significant improvement was observed (P > 0.05). 4).The gastric emptying of 39 of the 47 patients with contrast-enhanced ultrasound in group A was improved (P <0.05). The gastric emptying of 31 patients was significantly improved compared with that before surgery, and the gastric emptying of 8 patients was improved. The gastric emptying of the other 8 patients did not improve (P> 0.05); the gastric emptying of 36 of the 45 patients with iodine angiography in group B was improved (P <0.05), of which 31 The gastric emptying of one patient was significantly improved compared with that before surgery. The gastric emptying of 5 patients was improved, and the gastric emptying of the other 9 patients was not improved (P> 0.05). The improvement rates of gastric emptying after G-POEM evaluation by imaging examinations in groups A and B were 83.0% and 80.0%, respectively. There was no significant difference observed between the two groups (P > 0.05). 4. Conclusion Both the three-dimensional ultrasonography and iodinated water contrast agent fluoroscopy can evaluate the effect of g-poem. There is no significant difference between the two methods in the success rate and the coincidence rate. Because of the unique advantages of ultrasonography (no radiation / simple operation / high patient acceptance), the three-dimensional ultrasonography can be the first choice to evaluate the effect of operation. As a supplementary method, iodinated water contrast agent fluoroscopy can provide objective imaging data for clinic.