An all-optical broadcasting ultra-wideband (UWB) pulse shape modulation (PS M) technology based on the cross-gain modulation (XGM) in a semiconductor optical amplifier (SOA) has been demonstrated.In this novel scheme,two wideband travelin g wave SOAs are used,and the structure of the parallel SOAs is adopted to genera te the PSM signals.and three kinds of ultra-wideband PSM signals are generated at the smae time.As a consequence,this new scheme has the ability to transmit da ta among multiple users,and can be used as a theoretical basis of multiple accue ss communication.As the opposite working way is used.the scheme has an advantage in improving the extinction ratio (ER) of the output three ultra-wideband PSM signals.By using the software of OptiSystem7.0,the im pacts of the input signal pulse width,the optical power and the wavelength of th e las er on the generated three kinds of ultra-wideband PSM signal are numberically s imulated and studied.In addition,the transmission charac teristics of the generated PSM signal are discussed.The results show that the P S M signal has a good toleration to the pulse width,and the optimized ranges of ot her parameters are presented.