Abstract: Analyzing the existing super-short-scan algorithms, a new super-short-scan algorithm is proposed for local cone-beam CT (computed tomography) on FBP (filtered-back projection)basis with a scanning mode provided for the new algorithm to implement the piecewise circumferential combination. It is used to exactly reconstruct a volume of interest by using a data set acquired by super-short scan to make the reconstruction insensitive to noise. The cone-beam projection scan with piecewise circumferential combination proposed is such a scanning mode that the half-scan in circular trajectory is in combination with super-short scan, which is beneficial to improving the spatial resolution and image contrast of focal area and especially reducing the roentgen dose to patients.