Abstract: The design and development of new aeroengine is time consuming and expensive, while computational simulation is a promising method to solve this problem. Following the principle of the object-oriented technology and the structure of the engine, we designed and implemented a modular library of aeroengine, based on the non-linear mathematical equations of engine using Dymola/Modelica simulation software. The library is composed of the models for various aeroengine components: compressor, turbine etc., and the structure of the library is hierarchical, extensible and in compliance with standard. To test this library, we constructed a aeroengine model with mixed flow based on some NASA's data and the results of simulation were compared with those from the Gas Turbine Simulation Program. The comparison proves the validity and feasibility of the library.