Contract angle of cone segment, outlet diameter and length diameter ratio of cylinder segment influenced the jet cutting property of nozzle were studied by numerical simulation using simulation FLUENT. The results show that: nozzle with outlet diameter as 2 mm, length-diameter ratio as 2 and contract angle as 10 degree, has the highest axial velocity and largest impact energy，as well as greatest cutting capability. Jet axial velocity increases rapidly along the cone contract segment of nozzle, but increases first and then decreases along the cylinder segment. The largest value of cutting energy of jet impact does not distribute at the axis center of the impact plane, but on a circumference along the radius direction responding to the nozzle. 