  Three-form field can give rise to viable cosmological scenarios of dark
energy with potentially observable signatures distinct from standard single
scalar field models. In this study, the background dynamics of three-form
cosmology are investigated. Our analysis suggests that the potential of
three-form field should be runaway. We also investigate the possibility to
solve the coincidence problem by using the coupling of three-form field to dark
matter. Four types of coupling form are examined and we find that the coupling
of the form $Q = \sqrt{6}\Gamma (\dot{X} + 3HX)/\kappa$ provides the
possibility to solve the coincidence problem.
