  In this article, we assume that there exists a scalar hidden charm tetraquark
state in the $\pi^+ \chi_{c1}$ invariant mass distribution, and study its mass
using the QCD sum rules. The numerical result $M_{Z}=(4.36\pm0.18) \rm{GeV}$ is
consistent with the mass of the Z(4250). The Z(4250) may be a tetraquark state,
other possibilities, such as a hadro-charmonium resonance and a
$D_1^+\bar{D}^0+ D^+\bar{D}_1^0$ molecular state are not excluded.
