A new method of measuring the illumination distribution of the laser spot was studied. The method adopts the LabVIEW to drive the USB camera to collect the image of the laser spot, gets the 3D gray distribution and the illumination distribution of the laser spot after having processed the image with the computer, and can observe timely the exact illumination value of every pixel. The parameters of system design software could be set flexibly. With this method the data information of the laser spot could be collected dynamically and be processed real-timely. This method had been used for experiments teaching.