The mechanic function is theoretically described with the relationship between effective elastic moduli of saturated cracks of jointed rock mass and elastic moduli of rock，derived by O′Connell．According to the implication of the crack-density parameter in the relationship，the mathematical relationship is derived between the crack-density and the fracture tensor introduced by Oda under temperature effect．On the basis of the experiment results，under the effects of temperature and saturated water the regression expression of stress-strain and the compressive strength are obtained for the rock mass with single joint．The model is demonstrated by the results of test. The mechanical model can be used for THM coupling analysis on jointed rock mass.