Abstract: Aiming at the effect and stability of fan parallel operation in the mine ventilation system，and taking the optimization design of ventilation system for an antimony mine in Hunan as a engineering case，the three-dimensional model of mine ventilation system was established through the analysis of the characteristic curve of fan，and with the use of ventsim software.Then the ventilation effect of parallel operation for different types of fan was simulated and analyzed.It is proved that the optimization design above is feasible and reasonable.

Key words: Ventsim, Fan, Parallel connection, Numerical simulation