In this paper, the digital generation methods and the implementation techniques for Ultra-wideband LFM baseband signals are introduced. The two main digital methods for LFM waveform generation are firstly narrated and compared, and a generation scheme for Ultra-wideband LFM waveforms is presented according to the waveform storage method. Then, the key techniques in LFM baseband digital generation are discussed in detail. An experimental system has been implemented and tested. The results show that the scheme is feasible.