Abstract: Ultra-wideband (UWB) which is very suitable for short range and high data-rate wireless application has received much attention from the researchers all over the world, and the UWB modulation scheme is one of the research emphases. In this paper, a new time-hopping UWB modulation method called multi-pulse position modulation (MPPM) constructed by constant weight code (CWC) is proposed. The MPPM is based on the existing single pulse position modulation (SPPM) and employs more than one pulse in a symbol. The channel capacity and error probability of MPPM are derived over an AWGN channel respectively. Theory analysis and simulation results show that MPPM can get better communication performance than single pulse position modulation and pulse amplitude modulation (PAM) with lower receiver complexity under some given condition.