A Monte Carlo model is established to simulate transmission of 1.06 μm laser pulse in graphite smoke screen.Relation between transmittance and graphite particle size,smoke concentration,smoke thickness are analyzed.A convolution method is put forward to calculate waveform of pulse laser through smoke.For δ pulse laser and rectangular pulse laser with different width,time broadening is calculated.It shows that there is an optimal radius(0.16 μm) for graphite smoke particles,at which interference effect is the best for 1.06μm laser pulse.For rectangular pulse laser,the smaller pulse width is,the more remarkable change in pulse shape and temporal broadening are.For microseconds width laser pulse,pulse shape changes and temporal broadening are not obvious.