In the paper we have presented a critical analysis of a non-linear prey-predator system of Holling-type II. We have first investigated the criteria of stability of the steady - state, the bifurcation and the existence of a limit-cycle and its stability for the homogeneous state of the system. We have then studied the criteria of diffusion-driven instability and the shift of bifurcation point due to the influence of the diffusion. Finally, we have made a detailed non-linear analysis of spatial pattern formation arising from the bifurcation of the system beyond the onset of instability. © Research India Publications.