A new approach, the multipole theory (MT) method, is presented for calculat
ing three-dimensional (3-D) Laplace equation boundary-value problem. By the
mathematical deduction, the generalized MT series formula and its applied
laws are derived. The numerical analysis procedure and application of the M
T method in electromagnetic engineering have been presented. The MT method
is tested for accuracy by comparing the numerically calculated the capacita
nces against those analytically obtained for various electrostatic systems
associated with 3-D Laplace equation. The results obtained by the MT method
are also compared with the exact data reported in the literature. It has b
een proven that the MT method is an effective approach for calculating 3-D
Laplace equation boundary-value problems.