The mechanisms of rockburst are analyzed from the aspects of stiffness and energy by using "sample-machine" system.It is explained that the elastic energy storage before peak strength is the basic condition for rock dynamic failure.The experiments of uniaxial loading and unloading on the ore and wall rock samples from Hongtoushan copper mine are conducted,and rockburst proneness of them are evaluated with elastic strain energy indices.The results show that both ore body and wall rock have weak or strong rockburst proneness.