Abstract: To solve the problem of inefficient reading of massive point cloud data, this article presented a fast read method based on memory mapped file. By analyzing the working mechanism of the virtual memory system and the memory mapped file, the disk file was mapped to the virtual memory, and the large data volume file was accessed by the memory mapped file. The experimental results showed that the proposed method could effectively improve the reading efficiency more than 4 times by comparing with the traditional I / O-based data access method.