In order to study the development of bone and the effect of each single factor on the metabolism of bone during gestation age, a self-made rotating apparatus was designed. The limb bud of fetal mouse at the 16th day of gestation was examined with the techniques of X-roentgenography and histological slices. Comparing with the uncultued control limbs, the test limb cultured for six days showed longer bone length and higher bone density. The cultured bone cells showed active differentiation, proliferation and increased bone trabecula by histological examination. It is concluded that the cultured bone continued developing and differentiating, which confirming the feasibility and reliability of the method.