Atomic spectra data plays significant roles in the research of astrophysics measurements and plasma diagnosis,accurate and reliable atomic spectra data are very helpful in profound comprehensions of the nature of astrophysical sources and the characters of plasma.Focused on Fe XX ion,theoretical calculations on energy levels and magnetic dipole transition parameters of 1s22s22p3 ground configuration are performed using multi-configuration Dirac-Fock (MCDF) method in present work.Based on the relativistic computational code GRASP2k compiled within the framework of MCDF method,the relativistic effects and electron correlation effects in many-electron system are taken into account adequately,the fully relativistic atomic wave function is constructed with manageable size and most crucial correlation effects.Furthermore,considering and analyzing the competitions among the other physical interactions within the system,Breit interaction and quantum electrodynamics effect are treated in detail with perturbation approximation method.Then the accurate theoretical calculations on energy level structure and magnetic dipole transition rate,wavelength and weighted oscillator strengths of 1s22s22p3configuration for FeXX ion are accomplished.Compared with the existing experimental results,there lative differences of excited energies of atomic states and transition rates for magnetic dipole transition range from 0.175%~0.457% and 0.441% to 4.725%,respectively,good agreements are achieved.However,there is still insufficient in experimental data of wavelength and weighted oscillator strengths.The wavelengths computed in this paper agree well with other theoretical results available in literature,the maximum difference between them is only 6.138 88 .The results obtained are hoped to provide some valuable theoretical references for spectral experimental measurements.It can be inferred from present work that the fully relativistic MCDF method is suitable for various many-electron system and can be used in a widely range of applications for its accuracy and exactness in dealing with electron correlation effect and relativistic effects.The accuracy of results calculated meets the increasing data demands of storage ring experiment in which the highly charged ions can be prepared,and provides reliable theoretical reference datafor related studies,such as high-resolution spectroscopic measurement,astrophysics,plasma diagnosis,extra-nuclear inertial confinement and nuclear fusion,and so on.