As the conventional scan mode in helical cone-beam CT limits the field of view of the CT system, this paper analyzes the half-cover scanning of helical cone-beam CT and presents a new reconstruction method combined the Backprojected Filter(BPF) reconstruction and the cone-beam CT with half-cover scanning.This scanning method only demands more than half of cross section to be covered by X-ray beam at each view angle,and the width of the planar detector is about half of the conventional helical cone-beam CT, so that the cost of planar detector is saved.By combing the fan projection and 2D BPF, this paper researches a rebinned-weighted BPF algorithm for half-cover helical cone-beam CT,in which the projection data are firstly rebinned to half-cover fan-beam data, and then the weighted BPF are used in reconstruction. The results validate that reconstruction time with rebinned-weighted BPF algorithm has reduced to 3/5 that of the conventional helical FDK algorithm. Furthermore, the reconstructed value is more closed to the real value than that of FDK algorithm with large helical pitchs, and the MSE has reduced by half.