In this paper, we study a model of magnetohydrodynamics problem and prove the existence of weak solution to the stationary magnethohydrodynamic system in a three dimensional bounded domain Ω of class C 1,1. To our knowledge, all previous works consider the domain Ω simply-connected. Our proof is based on some weak estimates concerning vectors potential in negative Sobolev spaces. We also give some regularity results in L p-theory.