With self-consistent iterative method for solving the Hartree equation, precise numerical wavefunctions of helium 1snl configuration are generated to build up the LS term wavefunctions as basis sets. The magnetic fine structure of helium 10G—10M Rydberg states is calculated with the linear variation method, including both the exchange and magnetic interaction under the Breit-Bethe approximation. The calculated results agree well with the existing experiment data. Some ideas and discussions for further improvement are given.