The invention provides detection of a uniformity distribution condition of ArF excimer laser light intensity by adopting a probe step scanning method in optical projection exposure photoetching and designing or debugging. Excimer laser light intensity space distribution of each time cannot be prevented from influences of laser pulse time non-uniformity, so that total energy of a certain quantity of laser pulse and sub-energy of each detection point in a scanning light field are simultaneously measured within certain time under the control of sequential logic; the uniformity distribution condition of the light intensity is balanced through the ratio of the sub-energy to the total energy. The detection provided by the invention has the advantages of high detection precision, adjustable detection parameters and capability of meeting detection requirements with different precision requirements and realizing the detection of pulse laser light intensity uniformity; meanwhile, the detection also can be used for other fields needing to carry out pulse laser light intensity distribution uniformity tests.