  Given the recent constraints from the dark matter (DM) direct detections, we
examine a light GeV-scale (2-30 GeV) neutralino DM in the alignment limit of
the Minimal Supersymmetric Standard Model (MSSM). In this limit without
decoupling, the heavy CP-even scalar $H$ plays the role of the Standard Model
(SM) Higgs boson while the other scalar $h$ can be rather light so that the DM
can annihilate through the $h$ resonance or into a pair of $h$ to achieve the
observed relic density. With the current collider and cosmological constraints,
we find that such a light neutralino DM above 6 GeV can be excluded by the
XENON-1T (2017) limits while the survivied parameter space below 6 GeV can be
fully covered by the future germanium-based light dark matter detections (such
as CDEX), by the Higgs coupling precison measurements or by the production
process $e^+e^- \to hA$ at an electron-positron collider (Higgs factory).
