Abstract: In order to fill the data gaps in the voxels which were not intersected by any rays and depend on the initialized information, a new ionospheric tomography algorithm with smoothing method was proposed using the continuity and smoothness between the neighbor voxels in the tomography based on the multiplicative algebraic reconstruction techniques. Using the high precise dual\|frequency ground\|based GPS observation from the crustal movement observation network of China, the ionosphere density was reconstructed over China by the new technique. The retrieved ionosphere delay by the inversed result was compared with that from test stations, and the obtained density profile was compared with the ionosondes. The results demonstrated the efficiency and reliability of the new method.