The X-ray multi-energy computed tomography (CT), which primarily reconstruct images by collecting projections obtained by repeated circular scans at different energy, shows low scan efficiency and large dose of radiation exposure. The segmental multi-energy CT is studied. The tube voltage in every arc of a traditional circular trajectory CT scan is different to obtain the segmental multi-energy projection. Based on the accurate location of high frequency in the wavelet analysis, the gray-step of segmental multi-energy projection is corrected by the gray-step height of low frequency, and the segmental multi-energy CT imaging is realized. The simulation results indicate that compared with the hardening artifact correction mode, the method based on wavelet analysis eliminates the gray-step artifact, extends the energy spectrum information, and improves the reconstructed image contrast and hardening artifacts effectively.