Abstract: The formula deduced with Mathematica for dynamic modeling of flexible multibody systems is not simple enough and well formatted for programming.In order to code these formula into our system program of dynamic analysis for flexible multibody systems, a program module is developed to simplify and recode the formula using a recursion method.A test has been conducted which shows that the symbolic processing module is correct, effective and robust.

Key words: flexible multibody system, dynamic modeling, symbolic deducing