  We study the dilepton forward-backward and the longitudinal, normal and
transverse lepton polarization asymmetries in the heavy baryon decays of
$\Lambda_b\to\Lambda l^+l^-$. We show that the asymmetries have a less
dependence on the non-perturbative QCD effects. In the standard model, we find
that the integrated forward-backward asymmetries (FBAs) and three components of
the polarizations in the QCD sum rule approach (pole model) are $-0.13\
(-0.12)$ and $(58.3,-9.4,-0.07)%$ ($(58.3,-12.6,-0.07)%$) for
$\Lambda_b\to\Lambda\mu^+\mu^-$ and $-0.04 (-0.03)$ and $(10.9,-10.0,-0.39)%$
($(10.9,-0.2,-0.34)%$) for $\Lambda_b\to\Lambda\tau^+\tau^-$, respectively.
