Abstract: Current CAD software is slow to load large STEP neutral files, and its efficiency bottleneck lies in its analytic algorithm. The parsing algorithm based on single thread cannot meet the requirements of CAD application. This paper proposes a hierarchical parallel data parsing algorithm based on multithreading, which makes use of the multi-core parallel architecture adopted by current mainstream CPUs, and greatly improves the efficiency of STEP file parsing. According to the hierarchical characteristics of data in the model, the parallel acceleration of data parsing at each layer is carried out by using thread pool. The algorithm in this paper has been implemented in open source geometry engine OpenGE. In this paper, comparison between our algorithm and OpenCASCADE is performed to verify the running effects of the parallel algorithms. The experimental results show that the running speed of the parallel parsing program is about one times faster than that of the serial parsing program based on single thread and about one and a half times faster than that of OpenCASCADE.