Abstract: For a spatial linkage or a robot mechanism with helical pairs (H), its analysis or synthesis system of equations can not be transformed into a system of polynomial equations by triangle alternate, so the multiple solution problem of this mechanism can not be solved by the accurate homotopy method. In this paper, an approximate homotopy method (AHM) is suggested and configuration problem of the spatial 7H linkage is first solved by AHM. The method of this paper is suitable for solving the multiple solution problem of the spatial linkage or robot mechanism with H-pairs.