The invention provides a bone cement mixer and a stirring mechanism thereof, and belongs to the technical field of medical instruments. The bone cement mixer comprises a drug storage member, the drugstorage member includes a first chamber, the first chamber is used for accommodating medicines, the bone cement stirring mechanism comprises a stirring member, a connecting member and a moving member,the stirring member is located in the first chamber and is used for stirring the medicines, the connecting member is in snap joint with the stirring member, the connecting member includes an elasticportion and a connecting block, a stirring member connecting hole sleeves the elastic portion, the connecting block is fixedly disposed at one end of the elastic portion, the connecting block includesa first supporting inclined surface, the first supporting inclined surface is in contact with the stirring member, the moving member is slidably connected to the connecting member, the moving memberincludes a restraining portion, the restraining portion is in contact with the connecting block, and the moving member moves in the connecting member to drive the restraining portion and the connecting block to contact and separate so as to apply and to release the restraining on the deformation movement of the elastic portion. The mixer improves the efficiency of vertebroplasty.