  The B meson lifetime ratios are calculated to the order of $1/m_b^3$ in the
heavy quark expansion. The predictions of those ratios are dependent on four
unknown hadronic parameters $B_1$, $B_2$, $\epsilon_1$ and $\epsilon_2$, where
$B_1$ and $B_2$ parametrize the matrix elements of color singlet-singlet
four-quark operators and $\epsilon_1$ and $\epsilon_2$ the matrix elements of
color octet-octet operators. We derive the renormalization-group improved QCD
sum rules for these parameters within the framework of heavy quark effective
theory. The results are $B_1(m_b)=0.96\pm 0.04$, $B_2(m_b)=0.95\pm 0.02$,
$\epsilon_1(m_b)=-0.14\pm 0.01$, and $\epsilon_2(m_b)=-0.08\pm 0.01$ to zeroth
order in $1/m_b$. The resultant $B$ meson lifetime ratios are
$\tau(B^-)/\tau(B_d)=1.11\pm 0.02$ and $\tau(B_s)/\tau(B_d)\approx 1$ in SU(3)
symmetry limit.
