The electronic structure and photoresponse of p-type quantum well infrared photodetector (QWIP) are calculated by self-consistent method. The effect of distribution of holes in the momentum-space on the photoresponse of the device is studied. The calculation results show that the contribution of holes to the photocurrent depends on the distribution of holes in the momentum-space, so the density of holes and the temperature influence the photoresponse of the p-type QWIP. The theoretical results agree well in the change of photoresponse of device with doping concentration and temperature in the experiment.