In this paper, we study the properties of speckle fields emitted multimode fiber-optic boundle under illumination of the He-Ne laser light. The difference among the speckle-fields emitted by the multimode fiber-optic boundles, which consist of fibers of different cope diameters, is discussed, and compared with the speckle-field of frosted glass. The rightness of conclusions has been verified by the experiments, and the field can be used in optical measurement and information processing.