In this paper, we used the time-of-flight (TOF) of a charge packet, that injected by a voltage pulse to calculate the drift velocity and mobility of holes in organic semiconducting polymers. The technique consists in applying a voltage to the anode and calculating the time delay in the appearance of the injected carriers at the other contact. The method is a simple way to determine the charge transport properties of organic semiconductors. The effect of charge trapping mechanism on the carrier mobility in the organic layer is investigated and it was shown that at higher applied voltage, 100 V, hole mobility increases rapidly in comparison with lower applied voltage (50 V).