To investigate the clinical value of three-dimensional ultrasonography (3DUS) in obstetrics, various 3DUS rendering methods including surface mode, transparent mode and multiplanar mode were employed to scan 30 fetuses in second and third trimester by using the transabdominal volume transducer. The results showed that surface mode could vividly demonstrate the surface morphologic features of the fetuses, as well as the stereo-shape and the spatial relationship among the surface structures. The face, limbs, umbilical cord and outer genitalia of the fetus could be well displayed by surface mode. Transparent mode could reveal the bony structures under the surface, such as ribs, vertebrae, crania, etc. The result was not affected by the sophisticated curvature of these bony structures and the success rate was up to 100%. When rendered by multiplanar mode, the region of interest (ROI) could be viewed from different directions. It should be concluded that 3DUS could serve as a supplement to two-dimensional ultrasonography (2DUS). 3DUS might play an important role in prenatal diagnosis and enhance the diagnostic confidence level of the physicians.