For a commutative ring $R $ with identity, if $Nil (R)\not= J (R)$, can we deduce than $dim (R/J (R))<dim (R)$? ($R $ has finite $Krull$ dimension (=$dim$), $Nil (R)$=the set of all nilpotent elements, $J (R)$=the intersection of all maximal ideal of $R $) (Or if the inequality is not true, under which conditions it can be true)