Abstract:Through comparison of DTH hydro-hammer with hydraulic rock drill,two ideas are presented:(1)Thedevelopmetn of DTH hydro-hammers can be refered to the features of high hydraulic dressure,lowflow rate and high avilability engergy coefficiency of hydraulic rock drills;(2)The liquid spring property of drilling fluid playsan important role in improving the improving the operating performance of hydro-hammers.