Objective: To establish a culture method for primary mouse brown adipocyte precursor cells. Methods: Fibroblast-like cells were collected from C57BL/6j mice brown adipose tissue. The morphological changes of the cultured cells were observed,the intracytoplasmic lipid of the culture cells was determined using oil red O staining,and the expression of the brown adipocyte specific gene was determined by real time PCR. Results: The cultured fibroblast-like cells showed highly homogeneous appearance with active proliferation and differentiate into mature adipocytes. Oil red O staining,morphological observation,and expression of brown adipocyte specific gene UCP-1 verified these cells as brown adipocyte. Conclusion: Brown adipocyte precursor cells are present in C57BL/6j mice brown adipose tissue and possess the potential to proliferate and differentiate into mature brown adipocyte. The establishment of primary culture of mouse brown adipocyte precursor cells is important for furth studies of the function of brown adipocyte in vitro.