A cross-platform three-dimensional (3D) system, Acu3D, was developed to visualize human meridians and acupoints. Firstly, a 3D model of human body with meridians and acupoints was built as the basic data for Acu3D. The existing relevant standards and clinical knowledge were collected and organized to construct a knowledge-base which was integrated into the system. Then, Acu3D was realized leveraged by Unity3D platform, and was released to four different platforms. As the result, Acu3D displays location of meridians and acupoints visually and dynamically, compared existing real acupuncture model or 2D chart. It also can reveal details, such as meridian circulation, the spatial structure of acupoints, etc. Meanwhile, the cross-platform feature brings the possibilities to realize the multi-screen application scenarios by the same user interface. Thereby, it is expected to be widely applied in fields, such as teaching of traditional Chinese medicine (TCM), scientific research, science popularization, etc.