Abstract: When the resultant elimination method is used to solve the switching angles for selective harmonic elimination pulse width modulation（SHEPWM）technology,the physical memory usually will run out because of the intermediate expression swell.In order to solve this problem,apolynomial interpolation based method is proposed to convert the computing of determinants into computing interpolation points and the solving of linear equations,and the main procedure for parallel realization of this algorithm is given.The computation results show that this method is capable of effectively avoiding the problem of intermediate expression swell,and the maximum number of switching angles which can be solved is significantly increased.For a power converter with six switching points,the switching angles for the full range modulation index are computed and the correctness of the computed results is verified by experiment.