Low pressure rectiblock nozzle enhance the jet cleaning effect by using rectifying properties.Using FLUENT software, the effects of the rectiblock number and length of low pressure rectiblock nozzle were analyzed, and their effects to the jet velocity, the turbulence intensity and the dynamic pressure were gotten. The simulation results show: for the 8 mm nozzle, when the length of the rectiblock is 214 mm,number for 4 pieces,the turbulence intensity is low and the nozzle has a good ability of water flushing.