Objective To assess the feasibility of establishing a nude mouse model of endometriosis fibrosis of human origin and to determine whether endometrial mesenchymal stem cells are involved in inducing endometriosis fibrosis. Methods Four endometrial tissue specimens were collected and transplanted 1 ∶ 3 into 12 BABL / c nude mice by subcutaneous injection. The morphology and volume of the lesions were recorded. The nude mice were sacrificed on the 15th day after transplantation to observe the morphology of the lesions and their adhesion to the periphery of the abdominal wall. HE staining was used to judge the result of modelling, Masson staining was used to assess the extent of fibrosis, and immunofluorescence was used to track the role of endometrial mesenchymal stem cells in the fibrotic process of endometriosis. Results The volume of ectopic lesions in nude mice increased over time and showed restricted, vesicularlike changes. The tight adhesion of the lesions to the abdominal wall, endometrioid glands, and collagen fiber deposition were seen microscopically. The success rate of the modelling was 83. 4%, and the collagen fiber volume fraction of the lesions was significantly higher after modelling (P<0. 01) . Confocal imaging suggested that endometrial mesenchymal stem cells ( SUSD2⁺) differentiated into myofibroblasts (α-SMA⁺) in vivo. Conclusions The nude mouse model established by human allogeneic transplantation via subcutaneous injection was consistent with the lesion characteristics of endometriosis fibrosis. The modelling method is simple and feasible and provides a better reference model for further investigating the pathogenesis of endometriosis fibrosis. In addition, in vivo observations using the model indicated that endometrial mesenchymal stem cells are involved in inducing the formation of endometriosis fibrosis.