Hello All !! Is URL redirect is beneficial for old domain to new one ? if we redirect old URL to New one then there are possibility to gain ranking which already have old URL.

According to me, if your old url is not good or it give more problem for you, then in case url redirct is beneficial for old domain to new one. Unfortunately is nor good...

Yes, 301 redirect is the permanent redirect which passes between 90-99% of link juice to the redirected new domain.