In this paper,we discussed mainlythe variation of the rock density, S & P wave speed and calculated wave resistance with the pressure up to 1 000MPa. These deep-seated rocks were collected in Tianshui earthquake region. It was found that the state parameters of different kinds of deep-seated rocks, which didn't form at the same time, changed very little under high pressure. After the pressure up to 400 MPa,the variation of the rock density and S & P wave speed almost can't be found.We simply discussed the reasons of the phenomenon,and made practical error analysis on the parameters under 400 MPa pressure, The result shows that, without considering tempreture, the state parameters which were gained under 400 MPa pressure can completely replace the parameters under higher pressure (400 MPa-2000MPa) in practical application. so the rock state parameters (under 400 MPa characteristic pressure) are still significant for the artificial deep seismic sounding explanation and gravitation explana-tion.