A new method was introduced to fabricate porous coating and to control its porosity by changing spray parameters. Two models were constructed to simulate the deformation of molten particle and the deposition process of splats on substrate. Considering the gap-pore, step-pore and shield-pore in the presented models, the influence of spray angle on the porosity of coating was mainly investigated. Besides, other spray parameters which influence porosity were analyzed, including the velocity of spray gun, particle velocity and particle size. Moreover, a new forming method of graded porous coating is discussed.