This study was purposed to establish a convenient and efficient method for isolating and culturing mouse bone marrow mesenchymal stem cells (MSC). The femurs and tibias of mouse were taken under sterile condition. MSC were isolated and cultured with flushing- out bone marrow or collagenase-digested bone fragment or bone marrow plus bone fragment. MSC colony number and size were compared. Immunophenotype and differentiation ability were tested to identify MSC. The results showed that colonies from bone marrow plus bone fragment group came out earliest and the colony number was 20 ± 4 at day 4; there were 11.5 ± 2.5 colonies in collagenase-digested bone fragment group and 9.5 ± 1.5 in flushing- out bone marrow group. The total cell yields of MSC after passaging showed best in bone marrow plus bone fragment group. Flow cytometry data showed the cultured cells expressed Sca-1, CD44 and CD29, not expressed pan-leukocyte surface marker CD45 and endothelial cell marker CD31. The isolated and cultured MSC could differentiate into osteoblast at the osteogenic differentiation condition, or adipocyte at adipogenic differentiation condition. It is concluded that the method of bone marrow plus bone fragment is convenient and efficient for isolating and culturing MSC.