Abstract: For deficiencies of existing design methods of orthogonal coded signals such as notably computational complexity, limited coding length and limited signal number, a kind of random discrete frequency coding signal based on chaotic series is proposed in this paper, considering the attracting characteristics of chaotic series such as noise like behavior, initial value sensitiveness and easy for generation and use. The time-Doppler ambiguity function of the designed signal is induced in detail, the range and Doppler resolution are analyzed, and the pseudo-orthogonal property is discussed in this paper based on the signal coding model. Signal performances are compared with different chaotic series. The proposed signals present quite good performances in ambiguity function, pseudo-orthogonal property, easy generation and unlimited coding length and large signals number, and can be applied as a kind of promising radar signals.