Abstract: Design of beampattern and waveforms is attracting more interest in the field of MIMO radar system, and more working condition should be considered, such as the crowded spectrum. When continuous band is divided into several pieces, sparse frequency radar waveforms play an important role due to the special pattern of the sparse spectrum. In this paper, the idea of the joint design of the MIMO radar beampattern and the sparse frequency waveforms is proposed. On one hand, it ensures the detection performance of the energy concentrated radiation to the area of interest. On the other hand, sparse frequency waveform can avoid the interference between the radar system and other equipment working in the same frequency band. Given an ideal beampattern, we first formulate the optimization problem of obtaining the covariance matrix and then design the realizable beampattern with considering the both constant modulus and sparse frequency waveforms, where a cyclic algorithm is applied to solve these problems. The result with the joint design of the beampattern and waveforms by our proposed method is close to the ideal beampattern. Furthermore, the obtained waveforms have sparse frequency characteristics and good auto-correlation properties. The simulation results verify the effectiveness of this method.