Abstract: Among all kinds of reconstruction algorithms for 3D cone-beam CT, approximate algorithms are widely used in practice, because they have simple mathematics expressions, and can be easily implemented. The acquired reconstruction effect is good when cone angle is small. Among various approximate algorithms based in filtered back-projection, Feldkamp-type algorithms are the mainstream methods in practice all the time. The P-FDK(Rearrange the projection data then get reconstruction) is one algorithm of the extending FDK algorithms. To satisfy the voxel of the artificial division and considering the ralation between the defined voxel in real objects and others close to it, an improved technique for P-FDK algorithm was proposed, which is a 3D_6neighborhood P-FDK algorithm. The data used for reconstruction were also from the lab, the practical experiment indicated that the improved method would give a better result in the reconstructed image verge, and also the new method would restrain the noise to a certain extent.