The deep space exploration has extremely long-range,large delay of signal round trip,weak signal and other characteristics, pure tone ranging and PN ranging are unable to meet the demand of deep space ranging. A method of tone-code ranging that is suitable to the deep space exploration was proposed, and the transmitting and reception timing of the ranging signal was analyzed in detail. Because of the large forecast deviation of ranging signal return time caused by long-range and large delay, some effective protective measures were taken to reduce the forecast deviations of the ranging signal return time and avoid the match mistakes. The process of ranging capture and tracking were elaborated, in which the phase cycle of tone-code considered fully, and the improvement measures were proposed to improve the accuracy of range measurement. The ranging accuracy and capture time were analyzed; the results show that the tone-code Ranging proposed in paper is with higher accuracy and shorter capture time. Finally, the experiment was carried out on fully Digitized Control platform constructed by DSP and FPGA, compared with pure tone ranging, the accuracy of tone-code was higher, and range value is more stable.