TR tomographic scanning can detect large-scale components beyond the beam range, and has important applications in the field of ICT. One of the current reconstruction methods is to directly rebinding TR scan sinogram into standard parallel-beam sinogram without considering the influence of sector angle, and then reconstruct them using parallel-beam reconstruction method, which results in some errors in the reconstructed images. In this paper, a new rebinding algorithm is proposed. Through the coordinate transformation and interpolation calculation, the coordinates and gray scale information of the corresponding mapping points of the sampling points in the parallel sinogram are obtained in the TR scan sinogram. In this way, a complete parallel beam sinogram is obtained. Through simulations and experiments, it is found that the edge smoothness and artifacts are eliminated in both the sinogram and the reconstructed image obtained by the improved algorithm. The new rebinding algorithm can eliminate the errors of the existing rebinding algorithm. The TR scanning method can also achieve correct CT reconstruction when the fan beam angle is large.