Rock quality designation index is an important parameter for evaluating the quality of fractured rock mass; this index has been widely used in rock engineering

but the shortages of RQD (Rock quality designation index) itself has been recognized by engineer after a long term application and theoretical practices.The five shortcomings of RQD have been concluded as follows: (1) different angle between the direction of borehole and orientation of the discontinuities causes the different value of the RQD; (2) traditional RQD use 100mm as a threshold

but exactly this threshold can not stand for all the scale of the engineering

; (3) the number of the boreholes are limited to obtain the RQD

which causes difficult to estimate the quality of the rock mass in a large scale; (4) it is not economical to get the RQD by boreholes; (5) the RQD value is limited due to the number of the borehole are limited. Even the five shortages is recognize

but

RQD still represents its special vitality in the application of rock mass

five aspects for the RQD research and application are concluded out that scientists continuously put their efforts in the research of RQD for about half a century. Furthermore

the paper indicated that the main research methods and developing direction to improve on the meaning of the RQD.