Abstract: Encoding under WiMAX is a hot topic in today's telecommunication technology research. hhis paper intro- duced one of the most popular error correction encoding; Low Density Parity Check code (LDPC code)，discussed the basic principle and encoding-decoding design of LDPC code under WiMAX，put forward a LDPC code simulating plat- form by using Visual C++ characters, studied the procedure of simulation design, analyzed the impact to LDPC code performance under different realization method, and by analyzing and studying of simulation results, explained the feasi- bility, practicability and expansibility of Visual C++ applied in LPIX; encoding-decoding simulation.

Key words: LDPC, Simulation, C language, H matrix, Algorithm