Ultrasound is an inexpensive and widely used imaging modality for the diagnosis and staging of many diseases. In the past several decades, it has benefited from major advances in technology and has become an indispensable imaging modality, due to its flexibility and non-invasive character. In the last decade, research investigators and commercial companies have further advanced ultrasound imaging with the development of 3D ultrasound. Compared with two dimensional ultrasound imaging, it can provide a 3D image of the anatomy directly and localize the image plane much easier. This review focuses on three dimensional ultrasonic medical imaging patents filed in recent years between 2006 and 2010. The patents are classified into three classes: the hardware, software and applications. This paper will attempt to provide an appreciation of the recent advances in 3D ultrasound imaging research while glimpse the future development trend of 3D ultrasound imaging.