This paper presents the bit error probability (BEP) of impulse radio communication systems with Gaussian monocycle as the impulse. Results show that the BEP of asynchronous polarization randomized time-hopping (TH) impulse radio communication systems has no obvious relationship with the order of Gaussian monocycle, but has certain relationship with the width of Gaussian monocycle. The narrower the n-order Gaussian monocycle, the lower the BEP of TH impulse radio communication system.