Abstract:The rockburst tendency of rock specimen is an important parameter in describing the rockburst in underground excavation. In this paper,the complete stress-strain curves under uniaxial compression of marble specimens with different crystal size and length are studied. The crystal size of marbles are 0.2~0.5,0.5~1,1~4 and 4~6 mm respectively. And the ratio of length to diameter is 1,1.5,2,2.5 and 3,respectively. The rockburst tendency increases with the crystal size and decreases with the specimen length. The strength of marble decreases with the specimen length,which may results from the friction between the specimen ends and the loading head of the testing machine. But the relation of the strength to the crystal size is not clear.