A photonic-assisted generation scheme of fast switchable multi-format linearly frequency modulation (LFM) waveforms with a tuned bandwidth for a joint radar-communication (JRC) system is proposed and demonstrated. In this scheme, the up-, down-, dual-chirp LFM waveforms along with zero-value are obtained to form the joint waveform for carrying two bits of information per symbol. The bandwidth of the LFM waveforms can be tuned by adjusting the parabolic signal that drives the phase modulator (PM). The joint waveform can be used not only for radar ranging but also for the wireless communication. Simulation results show the 9–11 GHz up-, down- and dual-chirp waveform as well as the zero-value signal can switch at a rate of 64 MHz. The bandwidths of the LFM waveforms are tunable. The communication rate is up to 128 Mbit/s and the radar ranging resolution can reach up to 1.875 cm. The proposed scheme has a simple structure and can get good communication and range detection performance based on a joint waveform, and is expected to be used in the multifunctional JRC system.