Objective:To explore the application and value of high frequency ultrasound ileocecal localization combined with plasma fibrinogen (FIB) in the diagnosis of appendicitis in children with different pathological types. Methods: Sixty-two children with appendicitis admitted to our hospital from January 2017 to December 2018 were enrolled in this hospital. 60 cases were diagnosed as appendicitis by postoperative pathology. No positive diagnosis was found in the appendix for inflammation or other lesions. . Preoperative high-frequency ultrasound ileocecal positioning method and FIB method were used to conduct a comprehensive examination to evaluate the condition of the child. Kappa test was used to analyze the consistency of ultrasonography in the diagnosis of appendicitis in children with different pathological types. The accuracy, sensitivity and specificity of FIB level and combined diagnosis for appendicitis in children were calculated, and the combined diagnosis of ROC curve was drawn. Diagnostic value of appendicitis in children. Results:In this group of 62 patients, 60 cases were confirmed by surgery and pathology as acute appendicitis. 60 cases of acute appendicitis were diagnosed by ultrasonography. The overall coincidence rate of ultrasound diagnosis was 100% (60/60), but the diagnosis and pathological diagnosis of appendicitis were performed by ultrasonography. In comparison, the diagnostic consistency was generally (Kappa=0.746, P=0.000<0.001); the FIB of children with appendicitis gradually increased with pathological type, and the difference between the groups was statistically significant (P<0.05). The FIB level of children was significantly higher than that of the healthy group (P<0.05). The ROC curve analysis showed that the curve area (AUC) of FIB diagnosis of simple appendicitis, suppurative appendicitis and gangrenous appendicitis was 0.685, 0.743, 0.785, respectively; The optimal diagnostic thresholds for sexual, suppurative, and gangrenous appendicitis were 2.37 g/L, 3.68 g/L, and 4.72 g/L, respectively, and the sensitivity was 70.87%, 72.59%, 83.09%, and 75.09%, respectively; At the time of diagnosis, the curve area (AUC) of simple appendicitis, suppurative appendicitis, and gangrenous appendicitis were 0.853, 0.872, and 0.895, respectively. The sensitivity was 87.50%, 90.91%, and 95.45%, respectively. The specificities were: 75.00%, 61.22. %, 73.68% Conclusion: The application of ultrasound technology is accurate in the diagnosis of appendicitis in children, but it lacks higher sensitivity for less typical appendicitis. The use of high-frequency ultrasound ileocecal localization combined with plasma fibrinogen level can further improve various types of appendicitis in children. The diagnostic sensitivity helps to make timely treatment and a reasonable choice of treatment options.