Abstract: With the development of communication, radar and other fields, the congestion problem of modern electromagnetic spectrum environment is becoming more and more serious. In order to improve the efficiency of spectrum resources, this paper, from the point of view of radar transmitter, solves the problem of spectrum congestion by means of waveform design, and finds the waveform sequence which satisfies the requirements of good autocorrelation and energy constraint in the specific frequency band of the spectrum. In this paper, the convex optimization is used as a tool to establish the mathematical model, and then the Gauss randomization method is used to find the optimization signal after solving the convex relaxation of the problem model. However, the computational complexity of this method is high, so a new method is proposed. The core idea of finding waveform with fewer operations is to obtain the optimized signal by using a row (or column) element of a known matrix, and prove the relationship between the error expression and the known matrix at the same time. It provides a new way to solve the spectrum sharing problem. Simulation results show that the proposed algorithm has the advantages of good performance, stable and reliable signal to interference plus noise ratio（SINR） in feasible set, and can significantly reduce the number of operations.