Objective To isolate and culture primary small cell lung cancer ( SCLC) cells that retain the important characteristics and functions of the original tumor, and use them to construct a brain metastasis model of SCLC, as an animal model for drug development and the evaluation of patients with SCLC brain metastasis. Methods Fresh SCLC tumor tissue samples were collected from patients and transplanted subcutaneously into mice. The result ing patient-derived xenograft (PDX) mouse model of SCLC was assessed in terms of tumor presence, tumor size, and tumor growth. Primary cells were isolated and cultured from the tumor tissue after tumor formation, and their proliferation and invasion abilities were detected by cell scratch and proliferation tests. An SCLC brain metastasis model was constructed by injecting primary cells into the carotid artery, and the model was assessed in terms of its clinical manifestations and pathological observations. Results (1) A subcutaneous PDX model of SCLC was constructed successfully. The tumor passage time was about 56 days, and the tumor growth curve showed a logarithmic growth trend. (2)Primary L0 SCLC cells with tumorigenicity were successfully isolated and screened, and demonstrated strong cell migration and proliferation abilities. (3)An SCLC brain metastasis model was successfully constructed by carotid injection, and SCLC B0 cells with brain metastasis characteristics were isolated. Conclusions Primary SCLC cells were successfully isolated and cultured from SCLC tumor tissue samples, and a brain metastasis model using primary SCLC cells was successfully constructed.