Abstract: This paper introduces the principles of engineering geological dynamics of rockmass(EGDR).It points out that the mission of EGDR is to reveal the law of interaction between rockmass and geo-dynamic factors.EGDR basically studies the following aspects: the dynamic origin and features of the material and structure of rockmass,the crustal-dynamical environment of rockmass,the dynamic behaviour and process of rockmass,and the principle of geohazard prevention for rock engineering.The basic viewpoints of EGDR includes the following subjects.(a)The geo-dynamic genesis which means rockmass and its geological features are the results of crustal dynamic process.(b)Dynamic interaction that means the engineering behaviour of rockmass is the reflection of the interplay between rockmass and the geo-environment.(c) The point of process adjustment that infers the basic approach for engineering geohazard prevention is to adjust the interacting process between rockmass and the geodynamical environment.The following aspects have been described in details under the framework of geo-dynamics: (1)the dynamic genesis and geological features of rockmass,(2)the features of geo-dynamical environment of rockmass,(3)the fundamental mechanical behaviour of rockmass,(4)the features and behaviours of rockmass under high crustalstress,(5)the dynamic reaction of rockmass,and (6) the reaction of ground water in rockmass.