Abstract: Computation-intensive tasks in the data processing for global ionosphere mapping are analyzed. A parallel algorithm with OpenMP technique is proposed for data preprocessing incorporating normal equation matrix stacking, parameter pre-elimination, and normal equation matrix inversion. A validation experiment was executed on a single server. Results indicate that the computing time for rapid global ionosphere mapping is only about 10~13 minutes with a speedup of about six, the time for final global ionosphere mapping is only about 39-47 minutes and the speedup is about five. The precision for global ionosphere products are about 2.8~3.8 TECUs compared with IGS final products, and the final solutions are at higher precision, about 0.2 TECUs in contrast to rapid solutions. The parallel algorithm proposed in this paper is very useful for the optimal testing of global ionosphere mapping, when reprocessing long time span data extending over periods such as 10 years, as well as for the real-time ionosphere mapping.