In order to reduce the lossless compression time of the point cloud data files in large scene, avoid the time consuming and inputting errors caused by manual operation during data processing, this paper introduces LASzip lossless compression algorithm and the technology of OpenMP-based parallel computation, proposes a multi-core parallel batch compression algorithm for point cloud data files in large scene based on LASzip algorithm within the environment of the single machine of multi-core CPU. The experimental results show that compared with original serial algorithm, the parallel algorithm decreases obviously the compression time when the compression ratio is constant, achieving good speedup. The proposed optimization algorithm's compression and decompression time acceleration ratios reach 4.27 and 3.99, respectively, when 8 threads are used, the optimization effects are remarkable.