【Abstract】 Objective We aimed to explore the clinical and ultrasound features of fibroma of tendon sheath (FTS) and giant cell tumor of tendon sheath (GCTTS)．Methods 105 patients with GCTTS and 22 patients with FTS confirmed by operation and pathology were retrospectively analyzed. The clinical data, ultrasonographic features and misdiagnosis rates were compared.Results There was no significant difference in patients’ age and the location and number of lesions (P＞005). The prevalence of GCTTS in man was higher than that in women, while FTS was more likely to happen in men (P=001). The sonographic features of GCTTS and FTS were similar. Both appeared as hypoechoicmasses without calcification inside. We found no significant difference in echo strength, boundary and liquefaction of the masses (P＞005). 60% GCTTS cases (n=63) and 955% FTS cases (n=21) had regular morphology respectively. 733% GCTTS cases(n=77) and 955% FTS cases (n=21) located beside tendon. 733% GCTTS cases(n=77) and 500% FTS cases (n=11) didn't have obvious blood flow (blood flow level 0I). There were significant differences in morphology, the adjacent relationship with surrounding tissue and blood flow signals of two types of masses at high frequency ultrasound. The difference in misdiagnosis rates between GCTTS (114%) and FTS (682%) were statistically significant (P＜005). Conclusion FTS and GCTTS have similar characteristics in ultrasonic imaging, both appearing as hypoechoicmasses, located beside tendons. Patients' gender and the morphology, the adjacent relationship with surrounding tissue and blood flow signals of two types of masses at high frequency ultrasound may provide important reference value for clinical identification.