Looking for the meaning of leave as verb, I found the following sentence, on the OALD:
Leave go of my arm—you're hurting me!
The dictionary says that the meaning of leave go is "to stop holding on to something," and that is synonym of let go.
Can I always replace let go with leave go?
Best Answer
As noted, this usage isn't common among Americans. But I think even in British English we normally only use leave go instead of let go in contexts where the "holding on" is literal/physical - normally to a part of the speaker's body (arm, hand. ear, etc.).
Thus, Leave go [of] my arm! is much more common than Leave go [of] his arm.
Also, you won't normally hear it used transitively, as "Leave me go!" (that's invariably "Let me go!").
FINALLY - here's a usage chart which should convince you to use let go rather than leave go...