This paper presents the results of the study on drilling and cutting performance of the drill jointly epuipped with water jet for mortar blocks by changing the parameters such as diameter of nozzles, jet pressure, traversing rate, bit rotation speed and preset drilling rate. The maximum jet pressure, the maximum flow rate used in the performance were 2000kgf/cm2, 48l/min respectively. Throughout the experiment, actual drilling rate and cutting depth were mainly investigated.
　It is revealed that the water jet can improve actual drilling rate by several times as fast as that of conventional drill and the actual drilling rate approaches to the preset drilling rate as the bit rotation speed increases. Further, the results show the cutting depth also increases as the jet pressure increases.