Abstract: The detected samples of ICT have variable sizes. Maximizing the imaging area of detector is meaningful. This paper uses detector offset to enlarge the FOV, and derives appropriate reconstruction algorithm. The algorithm uses Parker type function weighted redundant portion of the projection data first, then uses fan-beam filtered backprojection reconstruction algorithm to obtain a tomographic image. In experiment, we used an actual industrial CT system to collect projection data of a steel line-to-block and an aluminum alloy gearbox shell to verify the reconstruction algorithm. The reconstructed results prove the correctness and validity of the proposed algorithm, and the spatial resolution is consistent with the reconstructed result of standard scan, and the detector offset method can be used effectively in industrial CT imaging.