Abstract:There is an important difference between the properties of material mechanics and those of structural mechanics. The physical meaning of complete stress-strain curve of rock at each stage is discussed under true uniaxial compression. It is concluded that the curve before the peak basically expresses properties of material mechanics of rock and the curve after the peak expresses in fact reflects the viewpoint of structural mechanics. A new method is presented for determining the stress-strain curve for a rock cylinder with a medium thickness under uniformly distributed compression and has a good result.