The existing ultrasonic wideband ( UsWB) technology, when used in intra-body communications (IBCs), shows some shortcomings such as low rate and poor ability to resist multinode interference. Therefore, a direct-sequence ultrasonic wideband (DS-UsWB) technology was put forward. This technology can effectively resist the multinode interference. DS-UsWB adopts DS and ultra wide band (UWB) technology to simulate ultrasonic IBCs. That means to model the intra-body channel in k-Wave and simulate intra-body multinode communications with the impulse response of the channel model. The signal parameters, which are used to overcome the multi-path effect, are determined by analyzing the time delay characteristics of the channel impulse response. Both the analysis of system performance and simulation results verify that, compared with UsWB technology, DS-UsWB can effectively resist the multinode and multi-path interference, and achieve higher data rate and lower bit error rate.