Abstract: Strategy of detailed history method is summarized, depending on which code ITR(ions transport and reaction) was developed. Both basic method and impulse approximation method to select flight path of ions are complemented respectively. Numerical results agree with CORTEO and TRIM very well. Relation between two methods is discussed. We found reason of CORTEO results differ from TRIM's by limiting maximum of flight length derived by impluse approximation method. ITR has advantages of TRIM and CORTEO. Impluse approximation method reduces nuclear collisions simulated. Index technique is used to calculate scattering angle, which significantly improves efficiency of ITR.