Abstract: Transmitted reference ultra-wide band(TR-UWB) system is introduced,and the power spectral density(PSD) of conventional single user TR-UWB signals presented.For the multi-user circumstance,mathematical models of PSD of TR TH-PPM and TR TH-PAM signals are given.The PSD of TR-UWB signal contains a continuous part and a discrete part.The continuous part is independent from the reference pulses,while the discrete part is influenced by reference pulses.Reducing the amplitude of the discrete part can be achieved by decreasing the number of reference pulses,which depresses the performance of TR-UWB system.Theoretical deduction is verified by results of simulation.