A method for collecting multi-energy CT data is provided. A method of reconstruction from multi-energy CT scan is further provided, in which data collection is performed on the first-class object at voltage values of m sampling points of the first-class voltage varied periodically, to obtain n sets of multi-energy first-class scan data {1} and a data collection is performed on a double-cylinder correction phantom at the voltage values of m sampling points to obtain combination coefficients, and thus obtaining corresponding combination coefficients Cfirsti and Csecondi corresponding to the case that the first-class scan data is collected in the ith projection angle at the first-class voltage and the image vectors Xfirst and Xsecond are obtained by calculating a minimum value of the difference between the first-class scan data {yi} and the combination projection data CfirstiPi*Xfirst+Csecondi*Xsecond.
