  Several aspects about $\Lambda$-hypernuclei in the relativistic mean field
theory, including the effective $\Lambda$-nucleon coupling strengths based on
the successful effective nucleon-nucleon interaction PK1, hypernuclear magnetic
moment and $\bar\Lambda$-hypernuclei, have been presented. The effect of tensor
coupling in $\Lambda$-hypernuclei and the impurity effect of $\bar\Lambda$ to
nuclear structure have been discussed in detail.
