A floor typed spatial robot of abrasive water jet machining is designed, which can be applied to machine three-dimensional complicated work-pieces. Its merits are simple structure and flexible moving. The structure and transmission programmer are discussed in detail. The working range of the abrasive water jet robot is analyzed to meet the need of the various sized work-pieces. The motion of the each joint is realized by means of various transmission programmers. The precise movement of the robot is realized by the stepping motor, and the required power of the robot is calculated.