Based on guidemode characters of spatial soliton wavesuides and theory of coupling between two waveguides, it has realized a kind of all-optical steerable directional coupler using spatial soliton waveguides. When input site and corresponding POwer intensity of two spatial solitons change, the output site of the signal through coupling between the two soliton waveguides will change. Some factors such as ratio of soliton and signal wavelength, linear refractive-index of media and coupling length which have influence on the performance of the steerable all-optical directional coupler have been studied.