Aimed at the difficult problems about removing drill dregs in trenchless laying, the reverse circulation technology, for the first time, is applied in the trenchless techniques. In the paper, the power of mud pump for removing the drill dregs in traditional trenchless technique and in reverse circulation technique have been theoretical calculated, the result show that the former is more than the latter. The reverse circulation cutting cleaning techniques applied in the practice trenchless laying have greatly improved the rate of removing dregs in borehole.