Objective: The purpose of this study was to investigate the risk factors of children re-intussusception of hydrostatic reduction guided by ultrasonography. Methods: The clinical data and sonograms of 50 cases of primary intussusception in children were retrospectively analyzed. Clinical data (gender, age, presence of vomiting or bloody stool) and ultrasonic characteristics (intussusception location, diameter of intussusception “concentric circle”, presence of blood flow signal, presence of free peritoneal fluid, presence of enlarged lymph nodes) were analyzed. The risk factors affecting the re-intussusception were screened out by univariate analysis, the cutoff value of the “concentric circle” diameter of intussusception was obtained by the receiver operating characteristic curve (ROC). Binary Logistic regression equation was used to analyze the risk factors for the occurrence of the above mentioned duplicates. Results: Gender, age, vomiting, intussusception location and enlarged lymph nodes had no significant effect on the occurrence of re-intussusception. However, the diameter of intussusception “concentric circle” is more than 35mm, the occurrence of blood stool, the presence of peritoneal effusion and the no blood flow signal in the concentric wall of intussusception will significantly increase the probability of re-intussusception (P < 0.05). The dominant ratio (OR) of the bivariate Logistic regression analysis was: the diameter of the “concentric circle” of intussusception OR: 5.886, blood stool OR: 4.207, abdominal effusion OR: 4.123, no blood flow signal of the concentric circle of intussusception OR: 3.556. Conclusion: The diameter of intussusception “concentric circle” is more than 35mm, the occurrence of blood stool, the presence of peritoneal effusion and the no blood flow signal in the concentric wall of intussusception are the important risk factors for children re-intussusception of hydrostatic reduction guided by ultrasonography.