The present study represents a numerical simulation of the experimental diffusion combustion of liquified petroleum gas with pulsating air in a cylindrical chamber. The simulation focused on the effect of mixing air inlet square shape with pulsation combustion on the temperature, combustion products velocity,turbulent viscosity, carbon monoxide, mass fraction of nitric oxide and soot. The simulation is applied by Ansys fluent 16 commercial packages solving probability density function equation and large eddy simulation. The sinusoidal air inlet velocity had a frequency of 200 rad/s with 3.4 m/s velocity amplitude. Two air inlet ports are used circular and a square shape which all have an equivalent inlet area of 120 mm². The numerical results are compared to experimental results of circular shape and achieve an acceptable agreement. It is noticed that the excitation leads to widening of the flame zone and a decrease in the flame length by 55%, also the average temperature decreases from 2050 to 1650 K in square shape and from 1900 to 1600 K in circular shape. The mass fraction of carbon monoxide, nitrogen oxide, and soot are reduced by 23%, 88% and 60%, respectively due to the pulsation and the addition of the sharp corner to the pulsation reduced them by 30%, 92%, and 70%, respectively.