This paper presents the method and results of an experimental study of the ignition characteristics of samples of high-energy materials by multimode laser radiation. A uniform distribution of the radiation flux density over the end surface of a cylindrical sample is obtained by its rotation around the axis of symmetry with a given angular velocity of rotation. The effect of convective heat transfer of the end surface of the sample with the environment on ignition characteristics is eliminated by placing the sample in a cylindrical container. The results of experiments on ignition of pyroxylin samples by a CO2 laser with and without rotation of the sample are presented.