Laser parallel light curtain can be extensively used to measure the diameter of the object, the velocity and coordinate of the projectile, the density of projectile in target etc.The uneven distribution of light energy made timing er-ror, directly influencing the accuracy of measurement.The measurement of the uniformity of light energy distribution mainly provides data preparation and theoretical basis for the study of larger screen and dense target, and improves the pre-cision of the curtain tests.The energy distribution of laser spot is introduced theoretically, the design principle of the laser parallel light curtain is explained, the experiment of measuring parallel light uniformity was completed, and the measure-ment data use of the origin software was analyzed.The experimental results are conformable to the theoretical analysis, the feasibility of the measurement method is proved.