I wanna know whether " up on your mountain top" is an idiom? And if it is, whats its meaning? for example if some one gets on some body case and critisize him/her, if his, her answer is: " up on your mountain top" does it mean critisize yourself?
A Google Books search returns exactly one match for "up on your mountain top" in the sense that the OP seems to have in mind. From Bruce Norris, The Pain and the Itch (2008):
The sense of the phrase "up on your mountain top" in this excerpt seems to be "from your remote, elevated vantage point of smug, safe superiority." So it's safe to call it a criticism. However, if it's a common idiom, it's a relatively new one. A comparable phrase that incorporates a more familiar idiom is "from your ivory tower," where the "ivory tower" most often refers to academia but can refer to any position of isolation above the tumult of everyday concerns and behavior.