Abstract: Abstract Objective:To observe the biologic characteristics of RAW264.7 cells,and to validate the feasibility of RANKL-mediated differentiation of RAW264.7 cells into bone-resorptive Osteoclasts (OCs).Methods：RAW264.7 cells were treated with RANKL. RANKL-induced formation into OCs were observed after tartrate resistant acid phosphatase(TRAP) staining. Bone resorption pits were detected by scanning electron microscope. Results：RANKL-differentiated RAW264.7 cell cultures develop both TRAP+ mononuclear and multinucleated cells.It has the ability of generating bone resorptive pits. Conclusions：RANKL can induce RAW264.7 cells to mature OCs. RAW264.7 cells are easier to obtain and culture.So RAW264.7 cells can be used as a preferable preosteoclast model.This methods has good repeatability and feasibility.It represent a relatively homogeneous population of pre-OCs.

Key words: ligand of receptor activator of NF-κB（RANKL）, RAW264.7 cell, osteoclasts, tartrate-resistant acid phosphatase（TRAP）stain