Abstract: Energy shaping technology could be used to reduce artifact error and increase nondestructive testing accuracy.How to produce required spectrum is a key issue.This article proposes spectrums whose peak energy are 3 MeV,6 MeV and 12 MeV especially as required spectrum and discusses calculation method for energy shaping.In order to calculate related parameters,this article simulates X-ray spectrum produced by electron Linac with Monte-Carlo method,makes equation fitting for the X-ray spectrum and linear attenuation coefficients of shaping materials,decides final arrangement for shaping according to calculation results and verifies the arrangement with Monte-Carlo method.