从泵吸反循环工作原理出发分析了维持正常反循环的条件和措施。在此基础上提出了关键的工艺问题是合理确定混合液上返速度、适当控制混合液的岩屑含量和正确匹配井径与钻杆内径，并且叙述了确定上返速度、控制岩屑含量和计算Ｄ／ｄ比例的方法。 Starting from the working principle of pump suction reverse cycle, the conditions and measures to maintain normal reverse circulation were analyzed. On the basis of this, it is proposed that the key process problems are to determine the velocity of the mixture liquid, to properly control the mixture content and to correctly match the borehole diameter and the inner diameter of the drill rod, and to describe the determination of the upper return velocity, the control of the cuttings content and Method to calculate D / d ratio.