For multi-planar reconstruction in 3D ultrasound imaging, direct and separable 3D scan conversion (SC) have been used for transforming the ultrasound data acquired in the 3D polar coordinate system to the 3D Cartesian coordinate system. These 3D SC methods can visualize an arbitrary plane for 3D ultrasound volume data. However, they suffer from blurring and blocking artifacts due to resampling during SC. In this paper, a new multi-planar reconstruction method based on voxel based beamforming (VBF) is proposed for reducing blurring and blocking artifacts. In VBF, unlike direct and separable 3D SC, each voxel on an arbitrary imaging plane is directly reconstructed by applying the focusing delay to radio-frequency (RF) data so that the blurring and blocking artifacts can be removed. From the phantom study, the proposed VBF method showed the higher contrast and less blurring compared to the separable and direct 3D SC methods. This result is consistent with the measured information entropy contrast (IEC) values, i.e., 98.9 vs. 42.0 vs. 47.9, respectively. In addition, the 3D SC methods and VBF method were implemented on a high-end GPU by using CUDA programming. The execution times for the VBF and direct 3D SC methods are 1656.1ms, 1633.3ms and 1631.4ms, which are I/O bounded. These results indicate that the proposed VBF method can improve image quality of 3D ultrasound B-mode imaging by removing blurring and blocking artifacts associated with 3D scan conversion and show the feasibility of pseudo-real-time operation.