Cyclone separator is a type of mechanical dust collector that is used to filter solid particles from the incoming gas flow. The two vital parameters that affect the performance of a cyclone are the collection efficiency and pressure drop through the system. Both collection efficiency and pressure drop are strongly influenced by the geometry of cyclone separator. The geometric parameters that affect its performance are mainly cone height, cylinder height, dip tube height, inlet section etc. The main aim is to maximize collection efficiency and minimize pressure loss. This paper mainly focuses on variations of geometric parameters of a cyclone and analyzing its effect on the collection efficiency. In this paper the actual cyclone separator model was first validated by using experimental results and results obtained from the computations performed in ANSYS CFX. The actual model was then modified by changing its geometrical parameters like cylinder height, cone height, dip tube height etc. The CFD analysis of these modified cyclone separators was performed. Collection efficiency obtained from the analysis was then used as a means to select the final design of the cyclone separator. The model with maximum collection efficiency is then selected.