  We propose a new approach to understand hierarchy problem for cosmological
constant in terms of considering noncommutative nature of space-time. We
calculate that vacuum energy density of the noncommutative quantum field
theories in nontrivial background, which admits a smaller cosmological constant
by introducing an higher noncommutative scale $\mu_{NC}\sim M_p$. The result
$\rho_\Lambda\sim 10^{-6}\Lambda_{SUSY}^8M_p^4/\mu_{NC}^8$ yields cosmological
constant at the order of current observed value for supersymmetry breaking
scale at 10TeV. It is the same as Banks' phenomenological formula for
cosmological constant.
