For numerical prediction of internal turbulent flow field in conical diffuser, a computerized simulation models is performed and application software developed for the BFC numerical solution to turbulence model for near-wall and low-Reynolds-Number flows.Taken as example the internal turbulent flow field in fan conical diffuser with given expansion angle, area ratio and Reynolds number,the numerical prediction was performed with computerized simulation models and verified experimentally.Finally, the application prospects and profit expectations are previewed.