On this study, numerical analysis was performed for the 3 dimensional flow field of gas and particle phase for axial inlet cyclone, a part of dust collector. We applied FVM to visualize the gas phase. The flow was solved using ${kappa}-{varepsilon}$ turbulence model. The major parameters considered in this study were helical guide vane, inner diameter, length. Particle trajectory calculations were performed for the particle sizes of $5{mu}m{sim}75{mu}m$. The distribution curve of particle sizes was made of Rosin-Rammler function. The simulation results show various gas flows, particle trajectories on numerical models.