Abstract: The Random Pulse Repetition Interval Radon-Fourier Transform (RPRI-RFT) is proposed for long-time echo pulses coherent integration and Blind Speed Side Lobe (BSSL) suppression, which makes it a good resolution for low SNR target detection and parameters estimation under Doppler ambiguity of long-range stealth targets. By analyzing the quantitative relation between the random jitter of PRI with the mean of Doppler ambiguity side lobes and the variance of random noise spectrum modulation, it is cleared that increasing the number of pulses can reduce the effect of modulation noise. Furthermore, for the problem of cross range unit migration leaded by increasing pulses, RPRI-RFT is an effective method to achieve echo pulses coherent integration. Both theoretical analysis and simulation results show that RPRI-RFT can be used to reduce random noise while suppressing blind speed side lobes, thus significantly improving the detection and measurement ability of low pulse repetition frequency radar with long-range weak high-speed multi-targets.