Abstract: The recent research status of rock mass engineering and rock mass mechanics is briefly introduced in this paper,and the inconsisten cy of the current theoretical research result with the in-situ observation dat a and with the mechanical model of rock mass engineering is also discussed.It is stated in this paper that the right analysis result should be got from rock mas s mechanics simulating analysis and strictly according to the practical dynamic al situation in rock mass. Therefore the author has raised a new concept of "un loading rock mass mechanics" to conclude the mechanical research content of exc avated rock mass which has been verified by practical project in high slope and underground engineering.The mechanics research on the excavation unloading rock mass is no doubt the significant section of rock mass engineering and its mechan ics simulation analysis.