  The effects of intensity interferometry (HBT), which are mainly reflected by
the measured momentum correlations, have been fully discussed since 1950's. The
analogous momentum correlations between identical fermions are however less
argued. Besides the fermion statistics, the momentum correlations between
identical fermions are also determined by some other aspects, such as coulomb
interaction, spin interactions and resonances formation. In this paper, we
discussed the factors that influence the momentum correlations between
$\Lambda$'s, especially spin interaction. It is also argued that the momentum
correlations between $\Lambda$'s are affected significantly by the yield ratio
of $\Sigma^0/\Lambda$, due to the limitation of experimental measurement. The
mixture of $\Sigma^0$'s and $\Lambda$s would significantly weaken the measured
two-particle momentum correlations of $\Lambda$'s.
