The invention relates to the technical field of radiation detection, in particular to an inversion program based on a C++ language and ROOT data analysis. The inversion program is used for measuring aneutron energy spectrum, by accumulating a certain amount of statistics, a set of reversal probability curves of chips with the neutron energy are obtained; inversion probability distribution of eachchip is substituted into the energy spectrum inversion program to obtain the neutron spectrum; an energy spectrum inversion program can be developed based on the C++ language and a ROOT data analysispackage, a Bayesian method is adopted to inverse the neutron energy spectrum, inversion is easy to achieve by the program, when measuring the neutron spectrum in experiment, by accumulating a certainamount of statistics, a set of reversal probability curves of the chips with the neutron energy are obtained, the inversion probability distribution of each chip is substituted into the energy spectrum inversion program to obtain the neutron spectrum, and the energy spectrum inversion program is developed based on the C++ language and the ROOT data analysis package. According to the inversion program based on the C++ language and ROOT data analysis, through test verification, a test method can ensure the accuracy and validity of the results.