Abstract: ln this paper,the macro一joint body in rockmass is described as an initial damage. The anisotropicmacro一damage tensor of rockmass is proposed .The damage strain is presented,which is caused by joint jump dis-placement. Its equivalent continuum model is established in which the main variables are volume averaging stress andstrain. ln the meanwhile,in order to obtain the engineering geological information for determining the macro-damage behaviour of rockmass,the survey methods in situ in engineering geology are discussed.