Helmholtz coils produce uniform sinusoidal magnetic field in the center region, and the direction of magnetic field is approximate straight line, to help simplify the complexity of inverse problems. The simulation models of an 8-channel magnetic induction tomography measurement system are built, reconstructing conductivity distribution with filtered back projection algorithm. In the filtered back projection algorithm, the detected data is supplemented by the linear interpolation first, and then filtered by the Hamming filter, while adding a window filter to reduce the impact of around the coil from the divergence of the magnetic field. The different noise ratio of noise is added in the detected data to test noise suppression ability of the algorithm. The experiment results show that this filtered back projection algorithm can reconstruct the conductivity distribution under this model.