3D body dimensions extracting is the basis that 3D body scanner evolve in clothing applications. In this paper, the body point cloud is acquired by 3D body scanner developed by our team. The initial point cloud is processed for reconstructed body triangular mesh model which is used to extract the body dimensions. The methods of processing the point cloud and constructed body model are simply discussed and the detail discussion can be found in my paper that is being published. In order to calculate the body dimensions, the reference points are identified according to the characteristic of the feature contours. Then the body dimensions, including length size and girth size, are extracted. By measuring 10 feature sizes of different bodies, the factors that affect the dimensional accuracy is analysed. The result shows the method is effective to extracting the body dimensions.