Medical images are usually big data and manipulated by large-scale hardware and complex software platform. With the development of Internet technology, people tends to use more and more online applications instead of heavy-weighted traditional softwares installed locally. Researches on online medical images processing has just started. In this article, a light-weighted solution of 3-D visualization of medical images is presented. Combining of HTML5 features and WebGL technique, web browser can be used as 3-D visulization framework for medical images data of specific formats (such as vtk, nrrd etc), which are produced from the traditional imaging platforms (such as 3D-Slicer).