The invention discloses a method and a device for splicing strips of an airborne laser scanning system. The method comprises: using a three-dimensional normal distribution transformation algorithm as a splicing algorithm in strip splicing, dividing voxel units in point cloud data of the airborne laser scanning system, establishing normal distribution in the voxel units, mean values and variance of the normal distribution representing characteristics of the voxel units; and then establishing a similarity function, and obtaining offset of strips when value of the similarity function is maximum; and adjusting adjacent strips according to the offset, to finally splice a plurality of strips together. In addition, through contrast experiment analysis, methods and parameters on three aspects of sample rate before strip splicing, data organization method in a strip splicing process, and discretization are selected to be more proper. The method has higher robustness, shorter splicing time, and better splicing precision, and memory utilization rate of a computer is lower.