In general microfluidic devices operates at very low flow rates. Because of very low dimension of the channel and low flow rate fluid phase Reynolds number in general is very low. Owing to this it is a common idea that in case of microfluidics, inertia does not play any significant role but there are few novel applications where inertia plays important role. Two major examples are secondary flow generation in a microchannel and inertial migration of the particles. We aim to investigate the combined effect of secondary flow and inertial particle migration on particle focusing through numerical simulations and experiments (micro-PIV).