Abstract: This paper deduces the MT(Multipole Theory) general solution formula of computation electrostatic field problems with the complicated field domain,from the MT general solution formula of the special electrostatic field computation.The boundary shape parameter is also deduced and the laws under which an analytical solution can be obtained by the MT is introduced.The MT general solution formula is used to calculate two examples for checking its calculation precision.It is shown that the MT has a lot of merits.