In order to acquire high collimating neutral Cr atomic beam,a laser collimating field is designed which is composed of three groups of laser beams to collimate high temperature Cr atomic beam.To reflect better the uncertainty of atomic motion in actual status and the influence of atomic isotopes on experiments,Monte Carlo random method is used to simulate the atomic initial state in the actual state.Based on stress distribution of atoms in the laser collimating field,motion characteristics of neutral Cr atomic beam in the actual state are quantitatively analyzed under the laser collimating field,and this motion path in the three dimensional space and three dimensional distribution of atomic landing point status are analyzed.The results show that the maximum divergency angle decreases to 1.5 mrad in x direction and decreases to 1.6 mrad in y direction after collimating Cr atomic beam,and atomic flux increases twice.Study results provide more detailed data for experiment and more ideal cold atomic beam for further more precise nanometer grating and nanodots.