Abstract: In order to solve the problem of increasing congestion in RF spectrum environment, the problem of spectrum sharing by means of waveform design is deeply studied. In order to be close to engineering practice, a new method for designing constant amplitude signal is proposed. Firstly, aiming at the radar transmitter, the radar waveform meets the specific time domain and spectrum requirements and imposes constraints, and then the radar receiving filter is considered to receive the clutter. therefore, the optimization problem model is established to optimize the maximum Signal to Interference plus Noise Ratio (SINR). In this paper, a nonconvex fractional programming problem model is obtained. In this paper, a nonconvex fractional programming problem model is obtained. Finally, the step-by-step optimization method is used to decompose the problem into two optimization problems, and the nonconvex problem is relaxed to solvable convex problem. Then Gauss randomization method is used to obtain the optimal signal and multiple cyclic optimization. The simulation results verify the effectiveness of the algorithm. The detection signals designed by the method can coexist in the spectrum, and the SINR performance can be guaranteed.